• Proceedings of the KSR Conference
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• 2003.10c
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• pp.85-90
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• 2003

Among rail defects, the transverse crack, which has been the most dangerous fatigue damage, is developed from shelling near the rail running face and grows perpendicular to the rail surface. Moreover, the crack has occurred frequently fatigue damage during winter. Therefore, to assure the safety of railway vehicles, it is necessary to investigate growth behavior of transverse crack for rail steel. In this study, fatigue crack growth behavior of rail steel and its gas pressure welded part at room and low temperature are performed. The fatigue crack growth rate of the welded part was lower than that of the base part within a lower ${\Delta}K$ region at both room and low temperature, and this difference decreases with increasing the ${\Delta}K$ due to the decrease of the fracture toughness.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2001.11a
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• pp.77-82
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• 2001

This paper is contents that measure the ventilation rates and temperature by driving condition of exhaust fan, vapor, contaminant occurrence amount of carbon dioxide etc. In kitchen of apartment house. The ventilation rates in the apartment kitchen measured by Tracer Gas Method. And, temperature of when cook by gas table hood lower part 10cm and floor upside 10cm of kitchen central part, 120cm, 210cm heights measure. As ventilation rates measurement result, ventilation number of times was 0.7(number of times/hour) when did not to operate exhaust fan. but we were measured by 2.3(number of times/hour) when drove strongly. As temperature measurement result at cooking by gas table, temperature showed highest in hood lower part 10cm of case that do not operate exhaust fan. Temperature at kitchen central was most low in 10cm height in talc floor, and 210cm were measured highest. Concentration of carbon dioxide is very high by 4,350ppm after measurement time 10 minutes in state who do not operate exhaust fan at cooking by gas table.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2001.11a
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• pp.99-104
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• 2001

This paper is contents that experiment exhaust performance of contaminant by establishment height gas table and hood establishment height. Hood made to control from gas table to 10 centimeters space from 30 centimeters to 70 centimeters. Exhaust fan operated by 110V, 160V, 220V, and gas used propane gas. Center part appeared highest as result that measure wind velocity and temperature from hood lower part. Wind velocity from hood lower part was proved that dominate contaminant exhaust performance. Exhaust performance of carbon dioxide and heat showed that 30 centimeters case overmatches because establishment height of hood compares 80 centimeters. Case of carbon dioxide of exhaust performance by establishment height of hood overmatched more than heat.

• International Journal of Computer Science & Network Security
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• v.24 no.9
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• pp.21-29
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• 2024

Precoding of the orthogonal frequency division multiplexing (OFDM) with Walsh Hadamard transform (WHT) is known in the literature. Instead of performing WHT precoding and inverse discrete Fourier transform separately, a product of two matrix can yield a new matrix that can be applied with lower complexity. This resultant transform, T-transform, results in T-OFDM. This paper extends the limited existing work on T-OFDM significantly by presenting detailed account of its computational complexity, a lower complexity receiver design, an expression for PAPR and its cumulative distribution function (cdf), sensitivity of T-OFDM to timing synchronization errors, and novel analytical expressions signal to noise ratio (SNR) for multiple equalization techniques. Simulation results are presented to show significant improvements in PAPR performance, as well improvement in bit error rate (BER) in Rayleigh fading channel. This paper is Part II of a three-paper series on alternative transforms and many of the concepts and result refer to and stem from results in generalized multicarrier communication (GMC) system presented in Part I of this series.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.218-221
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• 2008

Hot Press Forming (HPF), an advanced sheet forming method in which a high strength part can be produced by forming at high temperature and rapid cooling in dies, is one of the most successful forming process in producing components with complex geometric shape, high strength and a minimum of springback. In order to obtain effectively and accurately numerical finite element simulations of the actual HPF process, the flow stress of a boron steel in the austenitic state at elevated temperatures has been investigated with Gleeble system. To evaluate the formability of the thermo- mechanical material characteristics in the HPF process, the FLDo defined at the lowest point in the forming limit diagrams of a boron steel has been investigated. In addition, the simulation results of thermo-mechanical coupled analysis of an automobile one-piece lower-arm part are compared with the experimental ones to confirm the validity of the proposed simulations.

• Journal of Chest Surgery
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• v.39 no.5 s.262
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• pp.415-418
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• 2006

When tracheal invasion of a malignant tumor or tracheal stenosis of a benign origin exists at the lower or anterior part of the trachea, tracheal intubation or conventional tracheostomy may be difficult, and in these cases a modified tracheostomy through the lower or lateral part of the trachea would be necessary. We present 6 cases of modified tracheostomy performed with satisfactory results in severe tracheal stenosis that developed in the lower or anterior part of the trachea.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.2
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• pp.3-14
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• 2004

This study was conducted to assess the possibility of the field application of the iceharbor-type precast fishway. When overflow depth of weir is 4.0 cm in model fishway, upper part velocities appear appropriate for upstream migration of fish and the lowest overflow wall (right line) in lower part has shown velocity distribution more or less inadequate for upstream migration. Except that right line, left and middle line revealed that velocities are appropriate for upstream migration of fish. Therefore, we concluded that this fishway owing to be not broad growth width of overflow velocities according to increasing discharges can correspond to variation of water level. Also We consider that various velocities in fishway were effective, because slow velocity line can guide flow for upstream migration. For low flow, the arrangement of different crest level or each overflow part (higher left, middle and lower right, or lower left, middle and higher right) was more effactive than unform crert level. Hole plays an important role as migration pass during drought and flood flow. Therefore, We concluded that this fishway can cope with water depth variation by various overflow wall height change and raise the field applicability with better performance hydraulically and structurally.

• Journal of Biosystems Engineering
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• v.30 no.2 s.109
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• pp.75-80
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• 2005

Mechanical characteristics of flower stalks (scapes) of garlic such as shear forces, cutting forces, and modulus of elasticities were investigated as a preliminary research to develop a mechanical harvester of garlic bulbils. The average shear forces of garlic scapes was 0.642 N and the maximum and minimum shear forces were 1.42 and 0.25 N, respectively. The shear forces generally increased as the diameter of garlic scapes increased. There was no correlation between the modulus of elasticity and the diameter of garlic scapes and the average modulus of elasticity of garlic scapes was around $2.40\times10^7\;N/m^2$ There was also no correlation between the cutting force and the diameter of garlic scapes. As the downward speed of blade increased, the cutting force of garlic scapes decreased and reversed to increase. The cutting forces of the lower part garlic scapes were lower than those of the upper part. The range of cutting forces of the lower and the upper part of garlic scapes were 3.88-4.04 N and 4.29-4.93 N, respectively.

• Journal of Korean Academy of Nursing
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• v.33 no.1
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• pp.60-70
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• 2003

Purpose: The study is designed to develop an educational CD-Program for prevention and control of obesity among primary school students. Method: The study is conducted from June 15, 2000 to April 15, 2002. Based on the course of program development suggested by Dick and Cray (1990), the study followed the planning, development, education and evaluation of a program. Result: The developed CD-Program consists 2 parts each for lower and higher grades of primary school students. The introduction part of the first trial for lower grade students uses quiz to encourage their motivations, the body proceeds with motion pictures and animations to trigger their interests. The introduction part of the second trial for the lower grades consists of remembering the exhibition lecture. The first trial for higher grades of primary school students builds on the contents of the low grades. Its body part, how to determine obesity and calculate ones own obesity, puts ones own weight and height in by the mouse. For the second trial of the higher grades, the body consists of life-style, diet, and regiments. Conclusion: The merits of this CD-Program are that to be possible an interaction between teachers and students.

• The Journal of Natural Sciences
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• v.11 no.1
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• pp.75-84
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• 1999

Benthic macroinvertebrate fauna in lower part of Han river was surveyed using ponar grab and basket sampler during May, 1995 through June, 1996.The benthic macroinvertebrates composed of 14 species, 12 families, eight orders, seven classes in three phyla. Three species of annelids, four species of molluscans, and seven species of arthropodes were collected. Annelids were collected from all sampling stations, Neanthes japonica was a dominant species. Biomass reached pick at station 4 and decreased in lower part. Biomass was so unstable that seasonal fluctuation of biomass could observed.