• Magazine of the Korean Society of Agricultural Engineers
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• v.34 no.2
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• pp.73-84
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• 1992

The TIDE, finite element model for the simulation of tidal flow in shallow sea was tested for its applicability at the Saemangeum area. Several pre and post processors were developed to facilitate handling of the complicated and large amount of input and output data for the model developed. Also an operation scheme to run the model and the processors were established. As a result of calibration test using the observed data collected at 9 points within the region, linearlized friction coefficients were adjusted to be ranged 0.0027~0.0072, and water depths below the mean sea level at every nodes were changed to be increased generally by 1 meter. Comparisons of tidal velocities between the observed and the simulated for the 5 stations were made and obtained the result that the average relative error between simulated and observed tidal velocities was 11% for the maximum velocities and 22% for the minimum, and the absolute errors were less than 0.2m/sec. Also it was found that the average R.M.S. error between the velocities of observed and simulated was 0.119 m/sec and the average correlation coefficient was 0.70 showing close agreement. Another comparison test was done to show the result that R.M.S. error between the simulated and the observed tidal elevations at the 4 stations was 0.476m in average and the correlation coefficients were ranged 0.96~0.99. Though the simulated tidal circulation pattern in the region was well agreed with the observed, the simulated tidal velocities and elevations for specific points showed some errors with the observed. It was thought that the errors mainly due to the characteristics of TIDE Model which was developed to solve only with the linearized scheme. Finally it was concluded that, to improve the simulation results by the model, a new attempt to develop a fully nonlinear model as well as further calibration and the more reasonable generation of finite element grid would be needed.

• The Journal of Korean Obstetrics and Gynecology
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• v.21 no.4
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• pp.169-182
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• 2008

Purpose: The purpose of this study is to find out the relations between the index of obesity by body composition analysis (EMI. %BF and WHR) and results of other oriental health examinations (QSCC II, HRV and APG) on some women. Methods: 114 women who were tested by oriental health examination between May 2006 and August 2008 were studied. Results: As a result of the study on the relations between the index of obesity by body composition analysis and sasang constitution, it was found that each of them had significant differences among themselves and Taeumin had the highest significance than other sasang constitution. As a result of the study on the relations between the index of obesity by body composition analysis and HRV, it was discovered that there was no significant relationship between BMI and WHR and HRV. However, %BF had negative correlations with autonomic activity, stress resistance and stress index. As a result of the study on the relations between the index of obesity by body composition analysis and APG, it was found that they had positive correlations with each other. Conclusion: In conclusion, there are significant relations between the index of obesity by body composition analysis and results of other oriental health examinations.

• Korea Science and Art Forum
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• v.19
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• pp.623-633
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• 2015

Use of technology through utilization of ICT (Information Communication Technology) in field study area is rapidly increasing. Thus, when applying ICT to experiential education, apart from experiential education contents in simple form, the demand for new high quality contents is increasing considering change in education paradigm focusing on creativity. As a result, high quality interactive experiential education content for developing self-directed future talents is required. As a result of this, the development of ARD-based ICT experiential education content system that enhances learning effect of students by integrating ARD-based (Augmented Reality Display) ICT and experiential education to promote existence and immersion is being tested. This paper aims to improve efficacy and achieve vitalization through case analysis of AR-based ICT experiential education content. As a result of case analysis, the composition of content for improving education content included 1) constant securing and strengthening of experiential education content, 2) necessity for development of participating education content by diverse age groups, 3) development of differentiated ICT experiential education content, and 4) securing professional manpower and development of content in connection with education process. Therefore, with the efficacy of ARD-based ICT experiential education content, this study can first, enhance bond between students, second, enable self-directed learning, third, increase practical understanding in contents that were difficult to control by textbook contents, and fourth, increase interest and immersion in learning. Therefore, the contents on new converging technology that can maximize the development of constant content and cooperation between ICT technology and pedagogy for educating creativity and autonomy of ICT experiential education content.

• International Journal of Highway Engineering
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• v.12 no.2
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• pp.107-113
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• 2010

In this study, the relative effects of low-chloride deicier(LCD) and two other deicing agents on the scaling of concrete were conducted in a series of tests at laboratory accordance with the ASTM C 672. The solutions concentration of deicers tested included 1, 4, 10%. Tap water was used as control. The amount of scaling was evaluated gravimetrically. As test result of deicer solution types, when applied to 4% solutions, surface scaling of concrete after 56 freeze-thaw cycles was produced significantly as about 9 times on LCD solution, as about 18 times on $CaCl_2$ solution, and as about 33 times on NaCl solution comparing with tap water. As test result of deicer solution concentrations, relatively low concentrations (of the 4% by weight) of deicer were produced more surface scaling than higher concentrations (of the 10% by weight) or lower concentrations (of the 1% by weight) of deicer. It show that the damaging concentration is of the order of 3~4% for previous research result. It appears that the mechanism of surface scaling is primarily physical rather than chemical. Also, the effect of chloride deicier types, freeze-thaw cycling, and air contents on the performance of concrete was experimentally investigated. The results show that the concrete specimens subjected to freeze-thaw cycling scaled more severely in exposure to deicing salt than those in non-exposure to deicing salt, weight losses of the specimens tested in exposure to deicing salt were twice as much as those tested in non-exposure to deicing salt. Relative dynamic modulus of elasticity of concrete specimens decreased more quickly in exposure to deicing salt than in non-exposure to deicing salt. Also, relative dynamic modulus of elasticity of concrete specimens in exposure to sodium chloride deicing salt was decreased more quickly comparing with exposure to LCD salt. It is also shown that the chloride contents according to concrete specimen depths was more largely in exposure to LCD salt. When concrete specimen is exposed to chloride deicing salts and freeze-thaw cycling, performance degradation in the entrained air concrete(AE concrete) retarded more considerably comparing with non-entrained air concrete(Non-AE concrete).

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.4
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• pp.57-67
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• 2014

The vigor condition of trees is an important indicator for the management of urban forested area. But difficulties in how to assess the tree vigor condition still remain. Previous efforts were limited in the 1) measurement of single indicator rather than using multiple indices, 2) purpose-oriented measurement such as for air-pollution effect or specific pathological symptom, and 3) ordinal-scale evaluations by field crews 4) despite human errors based on his/her experiences or prior knowledge. Therefore, this study attempted to develop a quantitative and objective methodology for assessing tree vigor condition, by measuring multiple modules and building the profile inventory. Furthermore, the possibility and limitations were discussed in terms of schematic frames describing tree vigor condition. The vigor condition of 56 flowering cherry plants in urban park were assessed by in-situ measurements of following eight items; growth of crown(Gc), growth of shoots, individual tree volume(Vol), plant area index, woody area index, leaf area index, leaf chlorophyll content(Lc) and leaf water content(Lw). For validation, these measurements were compared with the ranks of holistic tree vigor condition, which were visually assessed using a 4-point grading scale based on the expert's knowledge. As a result, the measures of each evaluation item successfully highlighted a variety of aspects in tree vigor condition, including the states of both photosynthetic and non-photosynthetic parts. The variation in the results depending on evaluated parts was shown within an individual tree, even though the broad agreement among the results was found. The result of correlation analysis between the tested measurements and 4-point visual assessment, demonstrated that the state of water-stressed foliage of the season (Lw) or the development of plant materials since sapling phase (Vol) could be better viewed from the outer appearance of trees than other symptoms. But only based on the visual assessment, it may be difficult to detect the quality of photosynthesis (Lc) or the recent trend in growth of trees (Gc). To make this methodology simplified for the broad-scale application, the tested eight measurements could be integrated into two components by principal component analysis, which was labelled with 'the amount of plant materials' and 'vigor trend', respectively. In addition, the use of these quantitative and multi-scale indicators underlies the importance of assessing various aspects of tree vigor condition, taking into account the response(s) on different time and spatial scale of pressure(s) shown in each evaluated module. Future study should be advanced for various species at diverse developing stages and environment, and the application to wide areas at a periodic manner.

• Journal of Food Hygiene and Safety
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• v.16 no.4
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• pp.333-341
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• 2001

The actual overall migration data obtained from plastic food packaging materials into food simulants under high temperature testing conditions as described in the regulations of European Union, USA, and Korea or Japan were compared. Overall migration values(OMVs) with non-fatty food simulants under high temperature conditions were observed to be generally below 2.5 mg/dm$^2$ except polyamides(CPA and PA 6,6) which were tested at 121$^{\circ}C$ for 2 hrs. As for the fatty food simulants, the OMVs with soybean oil were higher than other simulants. Among the films tested, PVC wrap showed higher OMVs ranging between 23.9 and 54.6 mg/dm$^2$than others. The OMVs were measured at higher level with the elevation of contact temperature and the extension of contact time, and in fatty food simulants rather than in non-fatty simulants. Under similar testing temperature and time conditions. the OMVs tended to be increased in polar films like PA with polar simulants, and contrarily in non-polar films like PO with non-polar simulants. It is noteworthy that a discrepancy with regard to the result of OMVs was observed for some films as a result of different migration testing methods and conditions of each country areas.

• Journal of Microbiology and Biotechnology
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• v.12 no.4
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• pp.583-591
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• 2002

Biodegradation of fat, oil, and grease (FOGs) plays an Important role in wastewater management and water pollution control. However, many industrial food-processing and food restaurants generate FOG-containing waste waters for which there Is no acceptable technology for their pretreatment. To solve these problems, this study evaluated the feasibility of effective FOG-degrading microorganisms on the biodegradation of olive oil and FOG-containing wastewater. Twenty-two strains capable of degrading FOGs were isolated from five FOG-contaminated sites for the evaluation of their FOG degradation capabilities. Among twenty-two strains tested, the lipase-producing Pseudomonas sp. strain D2D3 was selected for actual FOG wastewater treatment. Its biodegradability was performed at 3$0^{\circ}C$ and pH 8. The extent of FOG removal efficiency was varied for each FOG tested, being the highest for olive oil and animal fat (94.5% and 94.4%), and the lowest for safflower oil (62%). The addition of organic nitrogen sources such as yeast extract, soytone, and peptone enhanced the removal efficiency of FOGs, but the addition of the inorganic nitrogen nutrients such as $NH_4$Cl and $(NH_4)_2SO_4$ did not increase. The $KH_2PO_4$ sources in 0.25% to 0.5% concentrations showed more than 90% degradability. As a result, the main pathway for the oxidation of fatty acids results in the removal of two carbon atoms as acetyl-CoA with each reaction sequence: $\beta$-oxidation. Its lipase activity showed 38.5 U/g DCW using the optimal media after 9 h. Real wastewater and FOGs were used for determining the removal efficiency by using Pseudomonas sp. strain D2D3 bioadditive. The degradation by Pseudomonas sp. strain D2D3 was 41% higher than that of the naturally occurring bacteria. This result indicated that the use of isolated Pseudomonas sp. strain D2D3 in a bioaugmentating grease trap or other processes might possibly be sufficient to acclimate biological processes for degrading FOGs.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.939-942
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• 2007

Vacuum cleaner is a close life product that can remove various dusts from our surroundings. However well vacuum cleaner clean our environments, many people are looking away from it, due to its loud noise. Its noise causes a big trouble in the usual life, for example, catch calls, TV watching and discussing etc. To reduce these inconveniences, noise reduction methods and systematic design of low noise vacuum cleaner are studied in this paper. At first, sound quality investigation is performed to get the noise level and quality that make people TV watching and catch calls available. Based on the European and domestic customer SQ survey result, sound power, peak noise level and target sound spectrum guideline are studied and introduced. As a second, precise product sound spectrums are designed into each part based on the sound quality result. Fan-motor, brush, mainbody, cyclone spectrums are decided to get the final target sound based on the contribution level. Fan-motor is the major noise source of vacuum cleaner. Specially, its peak sound, RPM peak and BPF Peak, cause the people nervous. To reduce these peak sounds, high rotating impeller and diffuser are focused due to its interaction. A lot of experimental and numerical tests, operation points are investigated and optimization of flow path area between diffusers is performed. As a bagless device, cyclones are one of the major noise sources of vacuum cleaner. To reduce its noise, previous research is used and adopted well. Brush is the most difficult part to reduce noise. Its noise sources are all comes from aero-acoustic phenomena. Numerical analysis helps the understanding of flow structure and pattern, and a lot of experimental test are performed to reduce the noise. Gaps between the carpet and brush are optimized and flow paths are re-designed to lower the noise. Reduction is performed with keeping the cleaning efficiency and handling power together and much reduction of noise is acquired. With all above parts, main-body design is studied. To do a systematic design, configuration design developments technique is introduced from airplane design and evolved with each component design. As a first configuration, fan-motor installation position is investigated and 10 configuration ideas are developed and tested. As a second step, reduced size and compressed configuration candidates are tested and evaluated by a lot of major factor. Noise, power, mass production availability, size, flow path are evaluated together. If noise reduction configuration results in other performance degrade, the noise reduction configuration is ineffective. As a third configuration, cyclones are introduced and the size is reduced one more time and fourth, fifth, sixth, seventh configuration are evolved with size and design image with noise and other performance indexes. Finally we can get a overall much noise level reduction configuration. All above investigations are adopted into vacuum cleaner design and final customer satisfaction tests in Europe are performed. 1st grade sound quality and lowest noise level of bagless vacuum cleaner are achieved.

• Journal of the Korea Concrete Institute
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• v.18 no.5 s.95
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• pp.621-630
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• 2006

Twelve beams made of lightweight high-strength concrete were tested to determine their diagonal cracking and ultimate shear capacities. A total of 12 beams without(4 beams) and with lightweight(8 beams) were tested in a stiff testing facility, and complete load-midspan deflection curves, including the maximum capacities portion, were obtained. The variables in the test program were concrete strength, which varied 35.4 MPa, 65.3 MPa; shear span-depth ratios a/d=1.5, 2.5, 3.5, 4.5; and tensile steel ratio between 0.57 and 2.3 percent. Also, we divided beam by diagonal tension crack and ultimate shearing strength to propose an equation. In addition, it analyzed comparison mutually applying existing proposal and guide. $V_{cr}$ was as result that AIK recommendations and Zsutty proposal decrease more than a/d=2.5, increased some in Mathey's proposal equation. $V_{cr,\exp}/V_{cr,cal}$ showed tendency of overestimation according to increase of tensile steel ratio and compressive strength of concrete. On the other hand, $V_{cr,\exp}/V_{cr,cal}$ is superior in conformability with an experiment result Zsutty's proposal among other equations. The proposal equation hew that expect $V_{cr}/V_u$, rationally about shearing strength. Therefore, shear strength an equation is considered to be utilized usefully evaluating capacity by change of the shear span depth ratio of lightweight concrete, tensile steel ratio, and compressive strength of the concrete in this research.

• Research in Plant Disease
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• v.20 no.2
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• pp.119-125
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• 2014

Root-knot nematodes represent a significant problem in cucumber, causing reduction in yield and quality. To develop screening methods for resistance of cucumber to root-knot nematode Meloidogyne incognita, development of root-knot nematode of four cucumber cultivars ('Dragonsamchuk', 'Asiastrike', 'Nebakja' and 'Hanelbakdadaki') according to several conditions such as inoculum concentration, plant growth stage and transplanting period was investigated by the number of galls and egg masses produced in each seedling 45 days after inoculation. There was no difference in galls and egg masses according to the tested condition except for inoculum concentration. Reproduction of the nematode on all the tested cultivars according to inoculum concentration increased in a dose-dependent manner. On the basis of the result, the optimum conditions for root-knot development on the cultivars is to transplant period of 1 week, inoculum concentration of 5,000 eggs/plant and plant growth stage of 3-week-old in a greenhouse ($25{\pm}5^{\circ}C$). In addition, under optimum conditions, resistance of 45 commercial cucumber cultivars was evaluated. One rootstock cultivar, Union was moderately resistant to the root-knot nematode. However, no significant difference was in the resistance of the others cultivar. According to the result, we suggest an efficient screening method for new resistant cucumber to the root-knot nematode, M. incognita.