• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.43 no.1
• /
• pp.49-53
• /
• 1998

Direct-seeding has major advantages such as labor and cost saving by eliminating preparation of seed bed and transplanting. But, it required increased input of fertilizers and pesticides because of the extended paddy period. Direct seeding in wet paddy (DSWP) gives faster growth and more uniform seedling emergence than direct-seeding in dry paddy. This research had an objective to develop an efficient N management practices for DSWP with split application of N fertilizer. A paddy field experiment was conducted to evaluate effects of starter N and N-topdressing which was delayed N application until 5-leaf stage, with comparison to transplanting (TP). Total amount of N application were two levels; 110kg and 77kg/ha. The N applications were split four times during rice growth stages; starter, topdressing at 5-leaf stage, top dressing at tillering stage, and topdressing at panicle initiation stage. DSWP had more tillers/$m^2$ than TP, but with the delayed heading. The DSWP plots which received N-topdressing at 5-leaf stage without starter N had higher leaf area index (LAI) and leaf greenness than the TP plot. Also, these DSWP plots had high leaf-N concentration at the heading stage, as calculated from leaf chlorophyll meter readings. Rice yield in DSWP with N-topdressing at 5-leaf stage was significantly higher than that in TP and in DSWP with starter N. Energy and N use efficiency were improved in DSWP with N-topdressing at 5-leaf stage. But, there were no significant differences in grain yield between the two levels of total amounts of N applications, 77kg and 110kg/ha. We concluded that starter N could not be used effectively by rice seedlings, but topdressing N at 5-leaf stage was an efficient N management for rice growth and yield in DSWP system.

• Journal of Korea Spatial Information System Society
• /
• v.10 no.1
• /
• pp.15-28
• /
• 2008

In ubiquitous sensor networks(USN) environment, it is essential to process region query for user-demand services. Using R-tree is a preferred technique to process region query for in-network query environment. In USN environment, USN middleware must select sensors that transfers region query with accuracy because the lifetime of sensors is that of whole sensor networks. When R-tree is used, however, it blindly passes the region query including non-existent sensors where MBR(Minimum Boundary Rectangle) of R-tree is Intersected by region of query. To solve in this problem, we propose a reconstruction of region query method which is a trie-structured Quad tree in the base station that includes sensors in region of query select with accuracy. We observed that the proposed method delays response time than R-tree, but is useful for reducing communication cost and energy consumption.

• Korean Journal of Ecology and Environment
• /
• v.49 no.1
• /
• pp.1-10
• /
• 2016

The increases of industrial and technological development and human activities have disturbed the balance of natural nitrogen (N) circulation. These phenomena have induced that large amounts of N are to be present in excess in air, soil and water environment. We investigated the effects of excess of reactive nitrogen ($N_r$) compounds on soil and water environment ecosystems through literature and case studies, and suggested the strategy of mitigating the acidification in soil and water ecosystems. $N_r$ moves to air, soil and water media, can be converted to different types, and interacts with other chemical compounds. As an efficient N management plan, the evaluation (application of monitoring and safety index) and the chemical restoration (research and development) of the acidification in soil and water environment ecosystems are required to minimize the effects of $N_r$ as well as policies to regulate the various emission sources and amounts of $N_r$.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.17 no.6
• /
• pp.1-10
• /
• 2013

Probabilistic nonlinear first ply failure loads of flat composite panels and nonlinear buckling loads of curved composite panels with cutouts are estimated to provide the more reliable main load carrying structure in the renewable energy industry and offshore structures. The response surface method approximates limit state surface to a second order polynomial form of random variables with the results of deterministic finite element analyses at given sampling design points. Furthermore, the iterative linear interpolation scheme is used to obtain a more accurate approximation of the limit state surface near the most probable failure point (MPFP). The advanced first order second moment method and the Monte Carlo method are performed on an approximated limit state surface to evaluate the probability of failure. Finally, the sensitivity of the reliability index with respect to transformed random variables is investigated to figure out the main random variables that have an effect on failures.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.12
• /
• pp.2682-2688
• /
• 2012

In this paper, we design and implement a electric current controller for ignition coil to measure the amount of current and to supply the additional current under vehicle driving conditions in spark ignition engines. The proposed controller can provide the stable current and prevent the overcurrent by measuring the amperage of primary ignition in real time. Also it enhances the performance of vehicle engine by controling the amount of ignition energy that make power increase and fuel burn more completely. The power and torque of the normal vehicle is evaluated as performance index for the experimental validation of the control module. The experimental results using dynamometer equipment show that after control module-mounted elevates the average of 10% more in both power and torque compared with before module-mounted.

• Korean Journal of Community Nutrition
• /
• v.17 no.4
• /
• pp.419-428
• /
• 2012

The purpose of this study was to evaluate nutrient intake and anthropometric parameters related to obesity in Korean female adolescents according to dietary diversity score. We analyzed data from the combined 2007-2009 Korean National Health and Nutrition Examination Survey (KNHANES). The subjects were 770 female adolescents. Nutrient intakes, Dietary Diversity Score (DDS) ) and Dietary Variety Score (DVS) were derived by using the data from the 24-recall method. The DDS was defined as the number of six food groups (cereals, meats, fruits, vegetables, dairy, fats and oils) consumed. The DVS was defined as the number of food items consumed. The average age of the subjects of the study was 15.02 years and the average height, weight, and BMI were 159.50 cm, 52.58 kg, 20.62 kg/$m^2$, respectively. The energy and nutrients intakes, percent of the recommended intake for nutrients in DDS = 5~6 group were significantly higher than those of the other groups. Calcium and vitamin C INQ in DDS = 5~6 group were significantly higher than those of the other groups. The average DVS of the subjects was 29.33. The most frequent style of food pattern was CMDFVO (cereals, meats, dairy, fruits, vegetables, fats and oils) = 111011. In conclusion, in healthy Korean female adolescents, food diversity intake variety did beneficially affect the intakes of calcium and vitamin C. Further studies are needed to confirm these findings.

• Korean Journal of Community Nutrition
• /
• v.17 no.6
• /
• pp.714-723
• /
• 2012

The aim of this study was to compare nutrient intakes, serum hormones (leptin, adiponectin, insulin), salivary cortisol and ${\alpha}$-amylase of middle-aged women by the percentage of body fat (% fat). Subjects were assigned to 3 groups by body fat (%) group I (27.5%), group II (32.5%), group III (37.7%). WHR of group II (0.97) was significantly higher than of group I, III (0.95) (p < 0.05). Nutrient intakes were not different among 3 groups. Serum leptin levels of group III ($16.53{\mu}g/ml$) were higher than in group I ($10.07{\mu}g/ml$), group II ($12.24{\mu}g/ml$) (p < 0.05). Salivary cortisol levels of group II ($0.39{\mu}g/dl$) were higher than in group I ($0.17{\mu}g/dl$) and group III ($0.15{\mu}g/dl$) (p < 0.05). Adiponectin concentrations were negatively correlated with TAS (r = -0.29) and positively correlated with HDL cholesterol (r = 0.27). Insulin levels were negatively correlated with total cholesterol (r = -0.33), Zn intake (r = -0.31) and positively correlated with WHR (r = 0.31). The overall anthropometric indices showed positive relations with leptin levels. Salivary cortisol levels were positively corelated with WHR (r = 0.28), total cholesterol (r = 0.31), MDA (r = 0.29) and intakes of SFA (r = 0.35) and MUFA (r = 0.3). Salivary amylase levels were positively correlated with overall nutrient intakes (energy, CHO, fat, cholesterol. Fe, SFA, MUFA, Zn, Na, vitamin $B_2$, r = 0.24-0.5) and was negatively correlated with HDL cholesterol (r = -0.34). These results suggested that 1) WHR would be a helpful index in the assessment of metabolic risk diseases. 2) Understanding of individual stress exposure should be considered in developing strategies for prevention and treatment of obesity.

• Korean Journal of Community Nutrition
• /
• v.17 no.4
• /
• pp.463-478
• /
• 2012

This study investigated the health and nutritional characteristics according to household income level and obesity in Koreans aged over 50 years based on the 2005 National Health and Nutrition Examination Survey. Subjects were classified into 3 groups by average household income with reference to the minimum monthly living expenses (MLE): low (n = 319, < 100% MLE), middle (n = 222, < 200% MLE), high (n = 411, ${\geq}$ 200% MLE) and each group was compared by BMI index. With increasing income level, the prevalence of systolic hypertension and hyperlipidemia was increased. In the low income group, serum total cholesterol, triglycerides, and fasting glucose were higher in the obese compared with the normal. In the middle and high income groups, the prevalence of hyperlipidemia and diastolic hypertension were higher in the obese. Subjects had nutritional imbalance, such as inadequate intake of calcium and potassium. With increasing income level, the percentages of protein and fat to total calorie were increased in addition to the intakes and density of nutrients. The obese in the low income group had higher intakes of energy, protein, phosphorus and higher consumption frequency of cereals and potatoes compared with the normal. It was shown that the obese of the middle and high income groups tended to have lower consumption frequency of Korean cabbage and higher frequency of fruits. The obese of high income group also had binge drinking habit. Therefore, this study suggests that specific approaches based on economic status should be considered in developing nutrition education program for the elderly.

• Applied Chemistry for Engineering
• /
• v.17 no.5
• /
• pp.547-551
• /
• 2006

In the reactor following the American standard test method (ASTM) D5757-95 and lab-scale fluidized bed combustor, the attrition characteristics of sand and ash of Korean anthracite were investigated. The attrition characteristics, such as particle size distribution of fly ash, attrition rate, and attrition ratio etc, were studied with variation of gas velocities. The particle attrition of ash was more active than sand which was generally used as a fluidized material and also the attrition index of ash taken by ASTM D5757-95 was 5 times higher than that of sand. The formation of fine particles continuously occurred due to particle attrition with increasing gas velocities. The following equation has been suggested for attrition rate of ash. $$\frac{dW}{dt}=-3.18{\times}10^{-7}(U-U_{mf})W$$.

• Korean journal of food and cookery science
• /
• v.15 no.2
• /
• pp.127-132
• /
• 1999

Dried noodles (somyon) were stored for 7 months at 25, 35 and 45$^{\circ}C$, and changes of water activity, amylograms and color of dried noodle at 4 week intervals were comparatively analyzed. The water activities during storage period were 0.43∼0.56 at all storage temperature. The breakdown of dried noodle by RVA(rapid visco analyser) increased as storage period increased. Color difference ($\Delta$E) was chosen for quality index due to the highest correlation coefficient between sensory score and color difference. The shelf-life of dried noodle was estimated from change of color, which was linearly increased as the storage period increased. The activation energy and Q$\sub$10/ value for color difference were 75.21 kJ/mol and 2.76 at 25$^{\circ}C$, respectively. Shelf-life of dried noodle at 25 were 27.9 months, respectively.