• 한국자동차공학회논문집
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• 제16권1호
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• pp.114-120
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• 2008

Recently, the nano-PM's number concentration emitted by diesel internal combustion engine has focused on attention because this particulate matters are suspected being hazardous of human health. In this study, The nano-PM mass and size of diesel passenger vehicles were measured on chassis dynamometer test bench. The particulate matters(PM) emissions of these vehicles were investigated by number concentration too. A condensation particle counter(CPC) system was applied to measure the particle number and size concentration of diesel exhaust particles at the end of dilution tunnel along the NEDC(ECE15+EUDC) and CVS-75 vehicle test mode. As the research result, the characteristic of vehicle test mode on the diesel nano-particle number and size distribution was investigated in this study.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.23-29
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• 2009

A sand-cone method is commonly used to determine the density of the compacted soils. This method uses a calibration container to determine the bulk-density of the sand for use in the test. The density of the test or compacted soil is computed on the assumption that the calibration container has approximately the same size or volume and allows the sand to fall approximately the same height as a test hole in the field. However, in most cases the size or shape of test hole is not exactly the same as the calibration container. There is certain discrepancy between sand particle settlement or arrangement in the laboratory calibration and in the field testing, which may cause an erroneous determination of in-situ density. The sand filling process is simulated in the laboratory and its effect on the determination of density is investigated. Artificially-made holes with different heights and bottom shapes are prepared to simulate various shapes of the test hole in the field. The sands with different gradations are used in the testing to examine how sand grain size influences the determination of density in the field.

• Geomechanics and Engineering
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• 제20권3호
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• pp.243-254
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• 2020

Due to the permanent damage to structures during earthquakes, soil liquefaction is an important issue in geotechnical earthquake engineering that needs to be investigated. Typical examples of soil liquefaction have been observed in many earthquakes, particularly in Alaska, Niigata (1964), San Fernando (1971), Loma Prieta (1989), Kobe (1995) and Izmit (1999) earthquakes. In this study, liquefaction behavior of uniform sands of different grain sizes was investigated by using the energy-based method. For this purpose, a total of 36 deformation-controlled tests were conducted on water-saturated samples in undrained conditions by using the cyclic simple shear test method and considering the relative density, effective stress and mean grain size parameters that affect the cumulative liquefaction energy. The results showed that as the mean grain size decreases, the liquefaction potential of the sand increases. In addition, with increasing effective stress and relative density, the resistance of sand against liquefaction decreases. Multiple regression analysis was performed on the test results and separate correlations were proposed for the samples with mean grain size of 0.11-0.26 mm and for the ones with 0.45-0.85 mm. The recommended relationships were compared to the ones existing in the literature and compatible results were obtained.

• 패션비즈니스
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• 제10권1호
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• pp.41-57
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• 2006

The purpose of this study were to provide dress forms and men's jacket blocks based on the analysis of their somatotype. As the result of the previous research, based on 1290 males of 20 to 54 year-old, the shapes of adult male were 20 and each body shape was classified by size factor, height and chest girth and master size was selected considering appearance frequency. Somatotype YS(master size: height 170cm, chest girth 91cm) and HD1(master size: height 170cm, chest girth 94cm) were selected to develop dress forms and men's jacket block in the study. The procedure and results were follows; 1. The dress forms of somatotype YS and HD1 were provide base on means of 61 body measurements and cross sections of shoulder, chest, waist, hip of subjects belong to each somatotype. 2. New men's jacket blocks of somatotype YS and HD1 were developed based on the body surface extracted by draping and the result of comparative investigation on the conventional jacket patterns by wearing test. Also the drafting methods of new men's jacket blocks were provided. 3. Wearing test by the sensory evaluation showed that the developed jacket blocks were estimated more highly than existing patterns.

• 패션비즈니스
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• 제12권3호
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• pp.136-152
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• 2008

The purpose of this study was to provide dress forms and jacket blocks for adult males based on the analysis of their somatotypes. As the result of the research conducted for this study that was based on 1290 males of 20 to 54 years-old, the shapes of adult male were 20 and each body shape was classified by size factor, height and chest girth. Also, master sizes were selected considering appearance frequency. XS type (master size: height 165cm and chest circumference 88cm), Yd type (master size: height 170cm and chest circumference 91cm), YI and AD2 types (master size: height 170cm and chest circumference 94cm) were selected to develop dress forms and their jacket blocks in this study. The procedure and results were follows; 1. The dress forms of XS, Yd, YI and AD2 types were produced base on means of 61 body measurements and cross sections of shoulder, chest, waist, hip of subjects belong to each somatotype. 2. New jacket blocks for XS, Yd, YI and AD2 types were developed based on the body surface developments through draping and the results of comparative investigation on the existing jacket blocks by wearing test. Also the drafting methods of new jacket blocks were provided. 3. The sensory evaluation by wearing test showed that the developed jacket blocks were estimated more highly in terms of chest's allowance, the front width's allowance, neck wrinkle, front allowance and overall appearance's fitness items than existing jacket blocks.

• Wind and Structures
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• 제4권3호
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• pp.213-226
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• 2001

Wind uplift rating of roofing systems is based on standardised test methods. Roof specimens are placed in an apparatus with specified table size (length and width) then subjected to the required wind load cycle. Currently, there is no consensus on the table size to be used by these testing protocols in spite of the fact that a table size plays a significant role in evaluating the performance. This paper presents a study with the objective to investigate the impact of table size on the performance of roofing systems. To achieve this purpose, extensive numerical experiments using the finite element method have been conducted to investigate the performance of roofing systems subjected to wind uplift pressures. Numerical results were compared with results obtained from experimental work to benchmark the numerical modeling. Required table size and curves for the determinations of appropriate correction factors are suggested. This has been completed for various test configurations with thermoplastic waterproofing membranes. Development of correction factors for assemblies with thermoset and modified bituminous membranes are in progress. Generalization of the correction factors and its usage for wind uplift rating of roofs will be the focus of a future paper.

• 한국안전학회지
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• 제17권4호
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• pp.45-51
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• 2002

In this study, the fracture characteristics of carbonized silicon grinding wheels were examined with tensile, compression, impact and bending test. The experiment was performed for the various grinding wheels with grain size #46, #80, and grade H, L, P, and one vitrified bond and one structure No.7. Also the centrifugal fracture rpm of carbonized silicon grinding wheels were measured and compared with the calculated values for the various wheel diameters and thicknesses. The results showed that the fracture tensile strength was $1.5~2.0Kg_f/mm^2$, and it was increased by decreasing grain size and increasing grade. The fracture compression loads were $1,600~3,000Kg_f$, and the inner stress was higher than outer's. And the absorption energy of impact test was 3.3~4.7 J, and it was increased by decreasing grain size but it was not effected by grade. The fracture bending stress was $0.1~0.2Kg_f/mm^2$, and it was increased by decreasing grain size and increasing grade. The centrifugal fracture rpm of carbonized silicon grinding wheel was about 8,500~12,000 and agreed well with the calculated value, and it was increased by decreasing diameter. However, it was almost constant for the reduction of wheel thickness.

• 대한임상전기생리학회지
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• 제10권2호
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• pp.37-42
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• 2012

Purpose : This study is to examine the effect of electrode size during transcranial direct current stimulation on hand function. Methods : By randomly assigning 26 right hand dominant subjects to two groups (I: carbon rubber electrode / II: disposable circular self-adhesive electrodes) with 13 subjects in each group depending on the electrode size, a positive electrodeof transcranial direct current stimulation was placed on the primary motor area (C4) and a negative electrode was placed on the left primary motor area (C3) and the stimulation was applied for 20 minutes.Hand function assessment before and after transcranial direct current stimulation were measured with JTT (Jebsen-Taylor hand function test). Results : According to hand function assessment by JTT, there were no interactions on both hands, and statistically significant differences according to time appeared in the main effect test. Conclusion : Regardless of the electrode size, it appears that transcranial direct current stimulation on the primary motor area activated hand function affected.

• 터널과지하공간
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• 제3권2호
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• pp.109-117
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• 1993

The existence and exact location of cavity is very important for the stability of the large underground storage house or building. Numerical method such as finite element method and finite diference methods are widely used because of model's complexity. Preliminary tests such as calculation step test, mesh size test and model size test were tried. Upper shadow zone and lower shadow zone can be calculated from 50% amplitude level of measuring data. From these statistical methods, the calculatied position of cavity coincided nearly with actual position of model testing cavity.

• Journal of the Korean Statistical Society
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• 제26권4호
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• pp.453-465
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• 1997

The family of power-divergence statistics conditional on margins is considered for testing homogeneity of .tau. multinomial populations with equal sample size and the exact Bahadur slope is obtained. It is shown that the likelihood ratio test conditional on margins is the most Bahadur efficient among the family of power-divergence statistics.