• Journal of the Korea Institute of Building Construction
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• v.9 no.2
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• pp.85-91
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• 2009

W/C and unit volume, which significantly affect quality of concrete related to strength and durability, are regulated at below $185kg/m^3$ for regular concrete generally used in standard specification for constructions. The aim of this research is to develop chemical admixture and find out its potential use by identifying characteristics of admixtures added to soft concrete and hardening concrete, of which content ratio of component for each type of admixtures is subject to change in accordance with unit volume within KS' allowable range. Sodium gluconate, polyoxyethylene nonylphenyl ether, poly carboxylic copolymer in slump, which is characteristic of soft concrete, are deemed highly sensitive while there is no air entrainment except for $10\sim70%$ in WE, WR component content ratio and NP. In hardening concrete, strength in general showed higher action in compressive strength and tensile strength than in plain strength. Use of proper AE agent and AE water reducing agent at the same time is deemed to be used as chemical admixtures capable of manufacturing high-quality, high-quantity concrete.

• Korean Journal of Metals and Materials
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• v.49 no.9
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• pp.671-677
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• 2011

Steel columns used in steel buildings are inclined to lose their strength when exposed to severe fire conditions, so fire resistance is required in most countries to protect against loss of life and building collapses. In Korea, the fire resistance of columns can be obtained by the fire test defined in KS F 2257-1, 7. The fire resistance of a steel column should be evaluated in terms of the column's conditions, such as various section types (H-section, hollow-section), the column's length and boundary conditions, and whether it is fixed or hinged. However, fire testing of steel columns is usually conducted on one standard-sized H-section over 3,000 mm, and the result is used as the column's fire resistance. This is not a reasonable way to ensure that a building can withstand fire conditions. In this study, to evaluate the possibility of calculating the fire resistance of steel columns with material properties of high tensile strength of SS 400, both load-bearing fire tests and calculation of steel temperatures were carried out. The results of temperature calculation were very similar to those obtained by fire test.

• Journal of the Korea Institute of Building Construction
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• v.24 no.5
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• pp.587-598
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• 2024

In this paper, we attempted to analyze vibration properties depending on construction deviations of concrete slab, and 12 specimens of 8 4 types were selected. The floor impact sound blocking performance measurement method was performed according to the standard weight impact source method among the KS F 2810 field floor impact sound blocking performance measurement methods. As a result, as the compressive strength of the slab increased, the amount of vibration decreased at a frequency of 31.5Hz, while the amount of vibration increased at 40 to 100Hz. As the slab thickness increased, the vibration level increased at a frequency of 31.5Hz and decreased significantly at frequencies between 40 and 100Hz. The level of vibration decreased with the thickness of the weakly bonded center point.

• Journal of the Korean Society of Safety
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• v.24 no.6
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• pp.136-143
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• 2009

The injuries as a result of fall accidents is the one of the most common kind of injuries in Korea, especially fall from height is the top most common kind for fatal injuries. Futhermore, the number of fall injuries in manufacturing industry has been steadily increasing from 2000 to 2007. In 2007 the number of fall fatal injuries increased 10.6 % in comparison with the number in 2006. These numbers are 6~17 times higher than those for foreign countries such as the U.K and the USA. So, it is needed to make a study to reduce these numbers for manufacturing industry. To get the goals, we did research as followings. First, this study analyzed statistics by industry, by fall height, by common agent and so on to gain an insight into real aspect of fall injuries. It showed that ladder is the commonly cited agent for manufacturing industry, and 3 risky activities ; the ladder work, the load/unload work, and the maintenance work. Secondly, this study made a survey of manufacturing workers for their understandings of the most 3 risky activities. It showed that 'tendency to work easily' and 'difficulty of applying measures due to inherent working conditions' are main reasons for workers not to implement the preventive measures against the fall accidents. Thirdly, this study tested the slip characteristics of ladder base and lungs. The tests were done based on ANSI standard and KS. In addition to the standard condition, this study performed slip tests in wet and sandy conditions and compared the results with the those of standard condition. It showed that friction coefficient is standard condition > wet condition > sandy condition, and the friction coefficient of ladder for sandy condition is measured to be reduced by 63.9% compared with that for standard condition. Finally, this study developed safety work models for using of portable ladders in consideration of the safety standards of foreign countries such as the U.K, the USA, and the Australia.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.535-541
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• 2020

FCAW is used mainly in the welding of carbon steel and alloy steel because it can be welded in all positions and can obtain excellent quality at sites with variable working conditions. Recently, many studies in Korea have estimated the fatigue strength, residual stress, and deformation, and to develop a fillet welding process. On the other hand, there have been few studies of the mechanical properties based on the strength, macro and magnetic particle test results for fillet welding. This study shows the following results through fillet welding, macro testing and strength testing using SM490A (solid-structure rolled steel) for thick plates using SS400 (rolled steel) for the upper plate and FCAW. The hardness test, macro test and magnetic particle test were then conducted. The hardness tests showed that all result values were smaller than the KS B 0893 standard values of 350Hv. The macro-test showed that each type of welded part was in a normal organic state and that there were no internal errors, bubbles, or impurities on the front of the welded part. Therefore, there were no concerns about lamination. The magnetic particle examination showed no problems.

• The Korean Fashion and Textile Research Journal
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• v.14 no.5
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• pp.834-845
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• 2012

This study was conducted to provide basic information on developing highschool-uniform pants with more suitable fit and to suggest a sizing system for highschool girls' uniform pants that adequately reflects their body figures. To understand the features of high school girls' lower body type, the body measurement values of 833 girls from 16~18 years of age based on Size Korea(2010) were analyzed statistically. For the classification of lower body type for high school girls, a factor analysis and cluster analysis were conducted. The collected data were processed with the programs SPSS 18.0 for windows. The results in this study are follows: The lower body types for high school girls were divided into 3 groups. Body Type A is average stature but the biggest circumference, Type B is the biggest stature and the medium body type, Type C is the smallest stature and skeleton structure. KS size intervals were used for frequency distribution of height and waist for the lower body. Sizing system of the uniform company and frequency distribution of sizes were compared. Using the two-way distribution of highschool girls' waist circumference and hip circumference, sizing system considering body type distribution and high frequency distribution section of sizes was suggested. This study established new sizing system depending on lower body fixed as 26 number of sizes. The most suitable standard is fixed as 12 number of sizes ; 64-88, 64-91, 67-88, 67-91, 67-94, 70-91, 70-94, 70-97, 73-94, 73-97, 76-97, 76-100. The coverage is also calculated. And the coverage of new standard was 63.5%. The continuous study on the uniform pants sizing system of the obesity types is required.

• Physical Therapy Korea
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• v.19 no.1
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• pp.46-55
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• 2012

The purpose of this study was to investigate the effect of the two different types of chairs on trapezius muscle activation during dictation tasks. Seventeen university students, each of whom were within ${\pm}1$ standard deviation of the mean Korean standard body size, voluntarily participated in this study. Surface electromyography was used to collect electrical signals from both the upper and lower trapezius muscles. Amplitude Probability Distribution Function (APDF) was performed to analyze the muscle activity. The findings of this study were 1) The backrest-point height of the auditorium chair and the height, length and width of the connected desk were shorter than what was suggested by the KS. Another difference was that the auditorium chair had a bigger angle of the backrest compared to the classroom chair. 2) Regarding within-subject effect the sole statistically significant difference was found between activation of the upper trapezius muscle. The upper trapezius muscle's %RVC in the APDF 10th-50th-90th percentile was statistically higher for participants sitting in the auditorium chair than for participants sitting in the classroom chair (p<.05). 3) There was an interaction effect between the 'two chair-types' and the 'two muscle-sides' in the APDF 10th-50th percentile (p<.05). 4) There was an interaction effect between the 'two chair-types' and the 'three gaze-direction' in the APDF 90th percentile (p<.05). The findings of this study indicated that maintaining a writing posture for a prolonged period of time in an auditorium chair significantly increased the left upper trapezius muscle activation compared to a classroom chair.

• Journal of the Korean Wood Science and Technology
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• v.39 no.6
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• pp.498-504
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• 2011

The purpose of this study was to investigate and develop an eco-frendly wood adhesive based on vegetable oil (especially soybean oil), the renewable and sustainable natural resources, using ozonification technology for the chemical structure modification. The waste soybean oil (WSBO) was reacted with $O_3$ at the rate of $450m{\ell}$(acetone) : $50m{\ell}$ (WSBO) for different times, 1, 2, 3 hrs. The investigation of the modified chemical strecture of the ozonied WSBOs were conducted using FT-IR. As ozonification time increased, the peak of the unsaturated double bonds was disappeared especially ozonized-3hrs and aldehyde or carboxyl peak appeared because ozonification broke the oil into small molecules. The plywood were made at $150^{\circ}C$ with 4 minutes hot-press time using the different ozonized 3 hrs WSBO/pMDI adhesives and were tested for the dry, wet, cyclic boil test according to the Korea Industrial Standard F3101 Ordinary plywood. The bond strengths gradually increased until 1 : 0.5~1 : 3, but it decreased 1 : 4, as the contents of pMDI increased. The results of the dry, wet and cyclic bond strengths the equivalent ratio was formed approximately between 1 : 2~1 : 3. And the 1 : 1~1 : 4 strengths met constantly the standard requirement of 7.0kgf/$cm^2$ (KS F3101). From the comprehensive view on the results of above experiment, it could be confirmed that ozonized WSBO/pMDI has characteristics of effective reactivity and wet stability showed as an excellent candidate of wood adhesive applications.

• Textile Coloration and Finishing
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• v.29 no.3
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• pp.162-170
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• 2017

Fastener tapes are widely used as auxiliary materials in textile products, and military textiles products are also applied. However, in Korea, the HL3-WA class of KS K 1309 was applied to military uniforms without consideration of the operating environment. Instead of adopting the standard of initial strength for Korean military uniforms, the US military applied the value after 3 washings, and presented different properties according to the items. Also in Japan, the standard was applied differently according to products in general clothing. The purpose of this study in to examine the quality level of fastener tapes used for military materials. The changes of tensile shear strength and peel strength of military and commercial fastener tape were studied after washing. As a result, the initial strength of the current military fastener tapes was higher than commercial one, but the strength retention rate was rapidly decreased as the number of washing. So it was confirmed that the decrease in strength was relatively lower than commercial one. It is necessary to improve the durability by adjusting the adhesive strength to suit the purpose of the product, and it is necessary to consider the priority of maintaining the durability according to the initial performance and repeated use according to the use environment, respectively.

• Journal of Korean Society of Archives and Records Management
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• v.5 no.1
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• pp.137-169
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• 2005

Some innovative strategies are being strongly promoted in records management system and institution of administrative agencies in Korea. To stabilize and institute these strategies, it is essential to improve the standards as well as legislations in the area of records management. The purpose of this study is to guide what kinds of standards to be developed and maintained, and to recommend some promoting principles and strategies. This study compares and analyzes international and foreign national standards to come up with improved standards in the national records management innovations. Four categories of standards are set for clearer explanation; national records management(KS ISO 15489), electronic records management, records management metadata, and others. Finally it suggests the promoting principles and strategies based on the analyses of the standard policies in USA and UK.