• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.330-337
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• 2006

Resistivity cone penetrometer test (RCPT) can be employed at a relatively low cost for delineation of subsurface contamination in situ, and then be supplemented with a minimum confirmatory sampling and laboratory testing program. While the resistivity measurement have potential to investigate the subsurface contamination, resistivity measurements alone will lead to some degree of ambiguity in the results. In this study, capacitance measurement was incorporated into the RCPT to overcome the ambiguity inherent in electrical resistivity measurements for delineating the subsurface contamination. This study is focused on verifying the applicability of resistivity and capacitance measurements on CPT module to provide information on contaminated subsurface by heavy metal and petroleum hydrocarbon. Laboratory model tests were performed to evaluate the sensitivity of the measured resistivity and relative capacitance on the water content and different types of contaminants. Test results show that simultaneous measurement of electrical resistivity and capacitance can give more reliable information on subsurface contamination.

• 한국도로학회논문집
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• 제16권5호
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• pp.9-18
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• 2014

PURPOSES : The objective of this study is to evaluate the applicability of the pitch, which is produced during SDA petroleum upgrading process, as a pavement paving material. In order for the purpose, the physical and chemical properties of the pitch are analyzed, and then the various plasticizers are applied in the pitch. METHODS : Two types of pitch are selected from oil refinery companies, which are owned the SDA petroleum upgrading process. Also, two types of asphalt binders, PG 64-22 and PG 58-22, are employed to compare with the pitch because these two types of asphalt binders are currently used as paving materials. For the chemical property of the pitch, the composition of SARA (Saturate, Aromatic, Resin, Asphaltene), the elementary composition, and the functional group are analyzed. For the physical property of the pitch, the basic material property tests, such as penetration test, softening point test, flash point test, ductility test, and rotational viscometer test, are performed. Also, the DSR (Dynamic Shear Rheometer) test and the BBR (Bending Beam Rheometer) test are conducted using asphalt binder specimens obtained by both short term aging (Rolling Thin Film Oven, RTFO) and long term aging (Pressure Aging Vessel, PAV) processes. The rheological property of each pitch type is evaluated as a function of temperatures and loading cycles. PG 64-22 asphalt binder is used as a control material. RESULTS AND CONCLUSIONS : The Pitch may not be suitable for the pavement paving material without modifications, but the pitch can be used as alternatives of modified addictive or asphalt. If low molecular component, such as saturate and aromatic components, are added in the pitch based on the development of various plasticizers, it has a strong possibility for the pitch to be used as a alternative. However, in order to verify the performance property of the pitch, further research is needed.

• 한국지반환경공학회 논문집
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• 제9권3호
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• pp.29-34
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• 2008

한국건설기술연구원(KICT)에서는 트리플 코어 바렐의 원리를 적용하여 기존의 연약지반 뿐만 아니라 사질토 및 풍화토 지대에도 적용이 기능한 대구경 샘플러를 개발하였다. 특별히 제작된 시료 절단 및 추출 장치는 다양한 종류의 채취 시료에 적용하여 시료의 교란을 최대한 방지 할 수 있도록 고안되었다. 샘플러 두부에는 적절한 강성의 스프링을 설치하여 슈(shoe)와 비트(bit) 사이의 거리가 변화하도록 하여 대상지반의 강성에 맞추어 효과적인 시료채취가 가능하도록 하였다. 대구경 샘플러의 적용성을 확인하기 위하여 일반적으로 시용되는 피스톤 샘플러와 대구 경 샘플러를 이용해 여러 대상지반에서 채취한 시료의 교란도를 비교 분석하였으며, 다양한 공학적 특성 또한 비교 분석 하였다.

• 한국터널지하공간학회 논문집
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• 제22권5호
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• pp.485-500
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• 2020

소규모 설비, 시공 용이성 등 다양한 장점으로 인하여 국내의 건설현장에서 광범위하게 사용되고 있는 그라우팅 관련 기술은 과거에 비해서 비약적으로 발전되었지만 품질의 균질성, 장기 내구성 및 환경공해 등의 문제점에 대한 개선 노력은 현재까지도 지속되고 있다. 최근 국내에서는 물유리계 그라우팅 재료가 갖는 낮은 강도와 내구성, 용탈현상 발생 등의 문제점을 개선하기 위하여 자기치유 물질을 이용한 그라우팅공법이 개발되었다. 자기치유 물질을 이용한 그라우팅공법은 주입재가 지반 내 물과 반응하여 생성한 결정 성장형 자기치유 물질에 의해서 주입재와 지반이 일체화되기 때문에 지반의 내구성 및 차수성 향상, 용탈방지 및 친환경성 등을 기대할 수 있는 것으로 알려져 있다. 본 연구에서는 △△터널 및 주변지반을 대상으로 자기치유 물질을 이용한 그라우팅공법의 예비시험 및 현장적용(표준관입시험, 현장투수시험, 공내 전단시험, 공내재하시험, 지시약반응시험 등)을 실시하였고 시공 전·후에 대한 실규모 시공조건에서의 주입범위, 차수 및 지반개량 효과 등을 비교, 분석하였다. 예비시험 및 현장적용 결과를 바탕으로 자기치유 물질을 이용한 그라우팅공법의 현장적용성 및 개량효과는 양호한 것으로 파악되었다.

• Communications for Statistical Applications and Methods
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• 제24권2호
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• pp.115-127
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• 2017

This paper proposes a Bayesian test for the equivalence of survival functions in multiple groups. Proposed Bayesian test use the model of Cox's regression with time-varying coefficients. B-spline expansions are used for the time-varying coefficients, and the proposed test use only the partial likelihood, which provides easier computations. Various simulations of the proposed test and typical tests such as log-rank and Fleming and Harrington tests were conducted. This result shows that the proposed test is consistent as data size increase. Specifically, the power of the proposed test is high despite the existence of crossing hazards. The proposed test is based on a Bayesian approach, which is more flexible when used in multiple tests. The proposed test can therefore perform various tests simultaneously. Real data analysis of Larynx Cancer Data was conducted to assess applicability.

• 한국철도학회논문집
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• 제8권1호
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• pp.101-109
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• 2005

Roller test rig is the test facility for acquiring the data related dynamic characteristics of rolling stocks handily. The test method using roller test rig could be convenient to Set information about hunting and others rather than using field test. However, adopting this method brings about the inconvenient calibration process for measured data. This kind of additional effort results from the difference of contact condition between field test and test roller rig. In this paper, the numerical approach is used to get the amount of calibration. The analysis results of the field test are compared with results of the roller test rig to know what kind of alternation happens according to the change of contact condition.

• 한국지진공학회논문집
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• 제7권5호
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• pp.57-66
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• 2003

본 논문에서는 동반된 논문에서 제안된 수정 병렬 IWAN 모델의 적용성을 금강 모래와 토요라 모래를 대상으로 비틂전단실험을 수행하여 검증하였다. 두가지 사질토에 대해서 대칭 하중과 불규칙 하중을 반복 재하하여 실험을 수행하였다. 제안된 모델의 변수는 다양한 상대밀도와 구속압 조건하에서 대칭 반복하중을 재하하여 결정하였다. 시험 결과, 하중반복회수가 증가함에 따라 발생하는 사질토의 반복경화거동을 수정 병렬 IWAN 모델로 표현 가능하였으며, Pyke(1979)에 의해 제안된 불규칙 하중 형태를 이용한 실험결과를 실험 조건이 유사한 대칭 반복하중 재하실험 결과로 얻어진 모델 변수를 이용하여 예측한 결과 실험 결과와 잘 일치함을 알 수 있었다.

• 환경영향평가
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• 제6권1호
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• pp.111-119
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• 1997

This study was carried out to suggest the best statistical test which may be used to quantify the change of water quality between two groups. Traditional t-test may not be used in cases where the normality of underlying population distribution is not assured. Three non-parametric tests which are based on the relative order of the measurements, were studied to find out the applicability in water quality data analysis. The sign test is based on the sign of the deviation of the measurement from the median value, and the binomial distribution table is used. The signed rank test utilizes not only the sign but also the magnitude of the deviation. The Wilcoxon rank-sum test which is basically same as Mann-Whitney test, tests the mean difference between two independent samples which may have missing data. Among the three non-parametric tests studied, the singed rank test was found out to be applicable in the quantification of the change of water quality between two samples.

• Nuclear Engineering and Technology
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• 제36권3호
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• pp.237-247
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• 2004

To investigate the applicability of automated ball indentation (ABI) tests in the evaluation of the tensile properties of cast stainless steel (CSS), ABI tests were performed on four types of unaged CSS and on 316 stainless steel, all of which had a different microstructure and strength. The reliability of ABI test data was analyzed by evaluating the data scattering of the ABI test and by comparing tensile properties obtained from the ABI test and the tensile test. The results show that the degree of scattering of the ABI test data is reasonably acceptable in comparison with that of standard tensile data, when two points data that exhibit out-of-trend are excluded from five to seven points data tested on a specimen. In addition, the scattering decreases slightly as the content of ${\delta}-ferrite$ in CSS increases. Moreover, the ABI test can directly measure the flow parameters of CSS with error bounds of about ${\pm}10\%$ for the ultimate tensile stress and the strength coefficient, and about ${\pm}15\%$ for the yield stress and the strain hardening exponent. The accuracy of the ABI test data is independent of the amount of ${\delta}-ferrite$ in the CSS.

• Communications for Statistical Applications and Methods
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• 제30권3호
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• pp.227-244
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• 2023

In this paper, a depth-based nonparametric test for a multivariate two-sample scale problem is proposed. The proposed test statistic is based on the depth-induced ranks and is thus distribution-free. In this article, the depth values of data points of one sample are calculated with respect to the other sample or distribution and vice versa. A comprehensive simulation study is used to examine the performance of the proposed test for symmetric as well as skewed distributions. Comparison of the proposed test with the existing depth-based nonparametric tests is accomplished through empirical powers over different depth functions. The simulation study admits that the proposed test outperforms existing nonparametric depth-based tests for symmetric and skewed distributions. Finally, an actual life data set is used to demonstrate the applicability of the proposed test.