• Journal of Welding and Joining
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• v.16 no.2
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• pp.84-92
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• 1998

On this study, the variations of hardness and microstructure were observed at he spot-welded part of 5182 alminum alloy sheets with thickness of 1.2 mm. The hardness of spot-welded part of aluminum alloy indicated the lowest value at nugget center. Also, the position where fatigue crack exists was investigated by surveying microstructure of the spot-welded sections. Mean load-deformation diagrams were obtained from static tensile test. Fracture was occurred completely within 5 mm after transforming elastic into plastic area. Fatigue test was stopped when the specimens of fatigue test had the final displacement of 0.2mm and measured fatigue bending angle and crack length. This study utilized them, investigated the relations between fatigue bending angle and fatigue crack length and made a estimation of the fatigue fracture life of resistance spot welded part of 5182 aluminum alloy sheet. The relative equation o fatigue crack length and fatigue failure life can be represented by {TEX}$L_{C}${/TEX}=α{TEX}$N_{f}^ {β}${/TEX}.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.997-999
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• 2005

In order for efficient Bluetooth Baseband functional test, Bluetooth SIG (Special Interest Group) provides with Test Suite Structure (TSS) in the Bluetooth specification version 1.1. Bluetooth Baseband hardware which needs to be authenticated should implement the test specification defined in the TSS part I.1 through I.3. In this paper, we discuss the method to verify and test a Bluetooth Baseband implementation based on the TSS version 1.0. Also, we describe various senario and implementation possibilities to perform the Bluetooth Baseband authentication test.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1417-1424
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• 2010

To provide more safe road and better travelling service for Expressway customer, we minimize settlement of bridge backfill and properly repair the occurred settlement. So, we devide this study to two parts one is construction part and the other is management part, in construction part we remove settlement occuring elements and in management part we grasp proper repair time, and then we produce general settlement management program. In construction part, for the purpose of developing construction method of reducing settlement, we developed construction method models and they are composed of abutment back section alteration and backfill material alteration by literature reviews and site investigation of backfill settlement. And then, we carried out laboratory model test and full size field test of some developed models.

• Journal of the Korea Institute of Building Construction
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• v.7 no.1 s.23
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• pp.79-84
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• 2007

Selection of proper root barrier as destination part of greening is very important in Root penetration resistance plan. To select proper root barrier, it need to understand composition of greening part, size, kind of plant, connection with waterproofing layer. In this point of view, we have establish greening on the roof or concrete structure, not been understand the structural mechanism. It means that we misunderstood about purpose of greening and using it. So, chosen materials and construction method was not proper for greening, it caused water leakage and decrease performance of concrete structure. Therefore, we would suggest 5 items of test methods considering environmental condition for green roof. Watertightness by water of greening part, root penetration resistance test by root penetration, bacteria resistance by must or bacteria in soil, chemical resistance by rain and chemical agent of fertilizer, and load resistance by soil depth, size of plant. These suggested test methods could be referred as guideline to test in green roof system because of not exist any performance appraisal guideline or standard. Consequently, it should be analysis as technical and institutional subdividing test methods and it need to study constantly as varied angles.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.4
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• pp.328-336
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• 2008

The shock tunnel as a hypersonic ground test facility was designed, constructed and its performance test was conducted to reproduce the high speed flow which the hypersonic propulsion system is encountered. The design points were understood and the conceptual design was completed using the quasi one dimensional operation analysis code. After that, the specific performance and compartment design were completed using CFD simulation as the part analysis. The facility was then constructed according to those design results and the performance test was conducted for various operation conditions. In this paper, we suggested the compartment design method using CFD analysis, construction process and various performance test results in detail.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.5
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• pp.636-642
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• 1999

The synthesis of the 3D images is the most important part of the virtual reality. The ray tracing is the best method for reality in the 3D graphics. But the ray tracing requires long computation time for the synthesis of the 3D images. So, we implement the ray tracing with software and hardware. Specially we design the hit-test unit with FPGA tool for the ray tracing. Hit-test unit is a very important part of ray tracing to improve the speed. In this paper, we proposed a new hit-test algorithm and apply the parallel architecture for hit-test unit to improve the speed. We optimized the arithmetic unit because the critical path of hit-test unit is in the multiplication part. We used the booth algorithm and the baugh-wooley algorithm to reduce the partial product and adapted the CSA and CLA to improve the efficiency of the partial product addition. Our new Ray tracing processor can produce the image about 512ms/F and can be adapted to real-time application with only 10 parallel processors.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.4 no.2
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• pp.29-33
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• 2008

As the measures of nuclear power plant utilities and manufacturers to reduce the defects of tube expansion region during manufacturing steam generators, many types of NDEs(Non-Destructive Examinations) are conducted to inspect the expansion region. The expansion region of tube is subject to degrade because of stress concentration induced by tube expansion, sludge pile and high temperature. So the inspections for tube expansion region have been reinforced. Liquid penetrant test, helium leak test, Bobbin profile test and hydraulic test are performed to confirm the integrity of tube expanded by hydraulic expansion method. Liquid penetrant test and helium leak test are used to inspect seal weld region on tubesheet end part. Bobbin Profile test is used to inspect fully the expanded region of steam generator tube. Hydraulic test finally verifies the integrity of seal weld region on tubesheet end part.

• Journal of the Institute of Convergence Signal Processing
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• v.4 no.2
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• pp.61-69
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• 2003

In this paper, we developed the U parameter test system which inspects the property of DC parameter for semiconductor products. The developed system is interfaced by IBM-PC. It is consisted of CPLD part, ADC (Analogue to Digital Converter), DAC (Digital to Analogue Converter), voltage/current source, variable resistor and measurement part. In the proposed system, we have designed the constant voltage source and the constant current source in a part. The CPLD part is designed by VHBL, which it generates the control and converts the serial data to parallel data. The proposed system has two test channels and it operates VFCS mode and CFVS mode. The range of test voltage is from 0[V] to 100[V], and the range of test current is from 0[mA] to 100[mA)]. The diode is tested. The test results have a good performance.

• Journal of the Korea Fashion and Costume Design Association
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• v.12 no.4
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• pp.137-147
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• 2010

This study set out to make experimental clothes by giving variations to the connecting part of a seamless sweater, propose designs and composition approaches to improve the wearing sensation and satisfaction with appearance through wearing trials, and provide basic data that would be of practical help to follow-up study on seamless knit and the growth of seamless knit in the Korean knit industry. The connecting part is the biggest characteristic and the most important part in seamless knitwear and affect the functionality and fitness of the clothes and the appearance of the armhole. The investigator thus made five different pieces of experimental clothes according to the composition methods for connecting part and put them to the test by a group of experts for appearance assessment. The assessment results were analyzed through Analysis of variance(ANOVA), and the items with similar results were put to the Duncan test for intergroup comparison. According to the analysis results, experimental clothes C and E received the highest evaluation in almost every assessment item, whereas experimental clothes A did the lowest appearance evaluation.

• Journal of the Korean Society of Clothing and Textiles
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• v.27 no.9_10
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• pp.1048-1059
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• 2003

This study focusses pattern draft and grading of jeans for women in their 20s, who consume jeans the most. Pattern was drafted based on existing patterns collected from companies. It is different from the existing educational patterns. It suggests new sizing system for twenties referring to sizes used companies and grading rule and method. he results were as follows; 1. Companies manufacture 2-8 sizes and they referred to the Korean Industrial Standards, KS K 0051, for their sizing system. 2. Drawing method for Pattern of the study had following measurements for each part: in the case of waist circumference, front part was W/4+1.5cm, back part was W14+2cm, front hip circumference was H/4-1.5cm, crotch line was the crotch length (practical measurement), hip circumference was (upper crotch line length)/5+0.5cm, front crotch part was 2.7cm, back crotch part was W/5+2.7cm, knee height was (the length of leg)/2+6cm and the circumference of knee and the tip of pants were 40cm. Through the wearing test on the subject of twenties, researched pattern received higher ratings, especially in appearance than the existing pattern. 3. 5 sizes system was made referred to the sizing system of companies and National Anthropometric Survey of Korean in 1997 Grading rule for 12 grading points of front part and 13 grading points of back part was suggested. Results of wearing test on the graded patterns showed high ratings similar to standard size.