• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.10a
• /
• pp.549-558
• /
• 2008

Well known and widely used in urban area and limited installation condition, a low noise and vibration piling method which has being called Bored Prefabricated Piling Method was reviewed in terms of design guide, and introduced a few case as well. Among the areas being applied of that method, a structural guide of architectural foundation was reviewed and compared to civil engineering foundation area to provide wider information for the foundation engineers. With introducing a few case application including pile load testing review especially dynamic testing in normal building foundation work, engineers may have a useful information on the design and construction of the piling method even different engineering area. It may also make enhancement a view of foundation engineering knowledge to various pile foundation area.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.04a
• /
• pp.496-499
• /
• 2008

The noise reducing devices installed on the noise barrier have been developed in many shapes and ways to reduce noise around road traffic areas. In this study, test and estimation method for the noise reducing device witch installed on the top of a noise barrier was suggested. For this, the authors have considered sound power flow around the device and sound pressure levels for the far field area. To estimate the area effect behind the barrier, area average of noise pressure level difference divided by two area, upper and bellow the sight-line. Comparing the attenuation difference of these areas, the tendency of noise reduction effect was studied according to type of noise reducing devices. Compared with noise shielding efficiency of the devices that using equivalent height of a simple barrier calculated by the SoundPlan, the commercial environment noise simulation software.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.29 no.4
• /
• pp.59-72
• /
• 1987

Although long-term runoff analysis is important as much as flood analysis in the design of water works, the technological level of the former is relatively lower than that of the latter. In this respect, the precise estimation model for the volume of successive runoff should he developed as soon as possible. Up to now, in Korea, Gajiyama's formula has been widely used in long-term runoff analysis, which has many problems in applying in real situation. On the other hand, in flood analysis, unit hydrograph method has been exclusively used. Therefore, this study aims at trying to apply unit hydrograph method in long-term runoff analysis for the betterment of its estimation. Four test catchment areas were selected ; Maesan area in Namlum river as a representative area of Han river system, Cheongju area in Musim river as one of Geum river system, Hwasun area in Hwasun river as one of Yongsan river system, and Supyung area in Geum river as one of Nakdong river system. In the analysis of unit hydrograph, seperation of effective rainfall was carried out firstly. Considering that effective rainfall and moisture condition of catchrnent area are inside and outside of a phenomenon respectively and the latter is not considered in the analysis, Initial base flow(qb)was selected as an index of moisture condition. At the same time, basic equation(Eq.7) was established, in which qb can take a role as a parameter in relating between cumulative rainfall(P) and cumulative loss of rainfall(Ld). Based on the above equation, computer program for estimation model of qbwas seperately developed according to the range of qb, Developed model was applied to measured hydrographs and hyetographs for total 10 years in 4 test areas and effective rainfall was estimated. Estimation precision of model was checked as shown in Tab- 6 and Fig.8. In the next stage, based on the estimated effective rainfall(R) and runoff(Qd), a runoff distribution ratio was calculated for each teat area using by computerised least square method and used in making unit hydrographs in each test area. Significance of induced hydrographs was tested by checking the relative errors between estimated and measured runoff volume(Tab-9, 10). According to the results, runoff estimation error by unit hydrograph itself was merely 2 or 3 %, but other 2 or 3 % of error proved to be transferred error in the seperation of effective rainfall. In this study, special attentioning point is that, in spite of different river systems and forest conditions of test areas, standardized unit hydrographs for them have very similar curve shape, which can be explained by having similar catchinent characteristics such as stream length, catchinent area, slope, and vegetation intensity. That fact should be treated as important factor ingeneralization of unit hydrograph method.

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.1760-1769
• /
• 2007

The cut slope sliding which has been frequently encountered in Pohang area has been reported due to the rapid reduction of shear strength in mudstone after being exposed to the air. Mudstone has characteristics that it has high enough strength and stiffness in a dry condition, but the strength and stiffness decrease in a wet condition with groundwater infiltration. The case study in this paper shows that mudstone which had enough strength in a boring stage has lost the strength after installing PRD steel pipe pile inducing an insufficient bearing capacity, which has been ascertained by the static load test. Test construction has been performed to investigate the most favorable method for increasing a pile bearing capacity in mudstone with various methods such as MSG (Micro Silica Grouting) around the tip and side of a pile, the perimeter grouting combined with Micro pile reinforcement, and concrete filling after tip reinforcing grouting. From the test construction, MSG has been turned out to be the most favorable method for increasing a pile bearing capacity in mudstone, which has been confirmed by the static load test.

• Journal of Mechanical Science and Technology
• /
• v.18 no.10
• /
• pp.1849-1858
• /
• 2004

For examining friction-factor characteristics of round-hole pattern surfaces which are usually applied on damper seals, flat plate test apparatus is designed and fabricated. The measurement method of leakage and pressure distribution along round-hole pattern specimen with different hole area is described and a method for determining the Fanning friction factor is discussed. Results show that the round-hole pattern surfaces provide a much larger friction factor than smooth surface, and the friction factor vs. clearance behavior yields that the friction factor generally decreases as the clearance increases unlike the results of Nava's flat plate test. As the hole depth is decreased, the friction factor is increased, and maximum friction factor is obtained for 50% of hole area. Since the present experimental friction factor results show coincident characteristics with Moody's friction factor model, empirical friction factors for round-hole pattern surfaces are obtained by using the Moody's formula based on curve-fit of the experimental data. Results of Villasmil's 2D CFD simulation support the present experimental test result.

• Journal of Korean Public Health Nursing
• /
• v.4 no.2
• /
• pp.5-13
• /
• 1990

The purpose of this study was to investigate physical self concept between high school boys and girls and to find various factors affecting them. For the Survey, 331 respondents for boys and 347 for girls were randomly selected from one coeducational high school in Seoul, from May 16 to May 19, 1990. The instrument used in this questionaire survey method was a part of Won Shik Jung's Physical Self Concept Scale for measuring Self Concept, it's reliability was' Cronbach a = 0.718. For the analysis. descriptive statistics were used by calculating frequencies, percentages and mean scores. $X^2-test$, t-test, and analysis of variance were employed to test the differences and statistical significance. The relationship between physical self concept and area variables was analysed by use of Pearson's correlation coiefficients. For the examine of various factors affecting physical self concept, multiple stepwise regression method was employed. The results of this study are summarized as follows: 1. There was no significant difference in physical self concept between male and female students. 2. The scores of physical self concept among the students were negatively correlated with their academic year, even though statistical signification was not found. 3. Physical self concept was classified into two areas; health area and appearance area. There was no significant difference in health area between boys and girls. But, the difference of health area was significant in accordance with the academic years. That, the scores of the health area are dropped as academic year going up. 4. Significant relationship was revealed among health area, appearance area, and physical self concept. The correlation between health area and physical self concept was the highest relationship (r = 0.71) The main factors affecting the physical self concept were (1) father's educational background (2) year (3) number of brother (4) religion (5) father's age. 5. As academic year going up, the rate of counseling with parents are dropped. In conclusion, the result of the study indicate that, a person managed the school health and parents can help students to promote their physical, mental, and emotional health by means of health education and counseling.

• Journal of the Korean Graphic Arts Communication Society
• /
• v.6 no.1
• /
• pp.13-39
• /
• 1988

Test colors are halftone dot printed at the rate of 10% halftone dot area by process inksblack, cyan, magenta and yellow ink. Reproduced colors are measured by the weighted-ordinate colorimetric method and the direct colorimetric method. The weighted-ordinate colorimetric method compare favorably with the direct colorimetric method, because the former has good regular changes of tristimuIus values, chromacity coordinates, excitation purities, value functions and has smaller errors of dominant and complementary wavelengths than the latter. All test colors classify with the Munsell renotation.tation.

• Fire Science and Engineering
• /
• v.26 no.6
• /
• pp.15-23
• /
• 2012

Indirect Test Method is often used instead of direct test method in test method for extinguishing performance of $CO_2$ extinguishing facility because of high cost, environment problems and difficulties of procedure. But in the danger facilities for a unit of nation, such as a petrochemical plant, a nuclear power plant, or etc. is better to verify the performance of the extinguishment through direct discharge test. In $CO_2$ extinguishing system for total flooding system installed in dangerous facilities in Korea, each protected area in surface fire and deep-seated fire had selected and verified of extinguishing performance of $CO_2$ extinguishing facilities. To get recognized as extinguishing performance, discharged $CO_2$ concentration to protected area should be equivalence with design concentration standards (NFSC and NFPA). The Design Concentration means that $CO_2$ extinguishing agent is considerate of concentration for percentage of allowance (20 %) from extinguishing concentration which available to control of flame. As test result, surface fire and deep seated fire in protected area is obtained $CO_2$ design concentration and maintained design concentration more than 20 minutes as deep-seated fire. Through this study, we introduced direct discharging test method and decision method. And furthermore, especially in the dangerous facilities as a unit of Nation, we suggested necessity about reliability of extinguishing facilities to use direct test method.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.10 no.2
• /
• pp.104-109
• /
• 2011

I present a method of aspheric surface profile measurement using 2nd derivative of local area profile. This method is based on the principle of curvature sensor which measures the local 2nd derivative under test along a line. The profile is then reconstructed from the data on the each point. Unlike subaperture-stiching method and slope detection method, 2nd derivative method has strong points from a geometric point of view in measuring the aspheric surface profile. The second derivative terms of surface profile is an intrinsic property of the test piece, which is independent of its position and tip-tilt motion. The curvature is measured at every local area with high accuracy and high lateral resolution by using White-light scanning interferometry.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.18 no.6
• /
• pp.84-90
• /
• 2010

This paper presents the shape optimization process for the automotive wheel bearing seal lip using the finite element method and the response surface method. First, to predict performance of the bearing seal lip, we used the non-linear finite element analysis. And then, we compared the analysis results with the test results to verify the finite element model. The objective function in optimizing process was obtained from results of the mud slurry test, which is one of many tests for evaluating performance of wheel bearing. After the mud slurry test for the four models which have the similar cross-sectional shape, we measured the wear area of the seal lip and the moisture content in grease. The objective function has been chosen by comparing the results of mud slurry test and characteristics of seal lip, such as contact force, contact area, contact pressure, and interference. Finally, within limited design parameters, we suggested the optimized shape of seal lip, which is expected to improve the wear and the sealing effect of it.