• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.6C
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• pp.259-266
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• 2011

Conducting statistical analysis of foundation resistance using sufficient number of well-performed load test results is prerequisite for the calibration of reliable resistance factors for foundation LRFD. In this study, a rational analysis method is proposed so that the proof pile load test results can be reflected in update of resistance statistical characteristics based on Bayesian theory. Then, resistance factors for driven steel pipe piles compatible with Korea foundation practices are updated by implementing this rational analysis method. To accomplish the resistance factor updates, (1) prior pile resistance distribution is constructed based on the results of pile load tests, which loads are imposed at least up to their ultimate limit loads. (2) likelihood function is obtained from the results of proof pile load tests, and (3) posterior pile resistance distribution is updated by combining these prior pile resistance distribution and likelihood function. The resistance factors are updated using the posterior pile resistance following the first-order reliability method (FORM). From the possible results of five consecutive proof pile load tests, the updated resistance factors vary within ranges of 0.27-0.96 and 0.19-0.68 for target reliability indices of 2.33 and 3.0, respectively. Consequently, it was found that the Bayesian theory-implemented method enables the updates of resistance factors in an efficient way when reliable resistance factors are not available due to the lack of well-performed pile load test results.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06b
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• pp.161-163
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• 2012

웹 기반 서비스의 수요가 급속히 증가함에 따라, 다양한 분야의 웹 어플리케이션이 개발되고 있으며 기능 요구 사항도 복잡해 지고 있다. 이에 따라, 구현된 소프트웨어의 복잡도가 증가되어 기능 검증을 위한 시험의 중요성이 대두되고 있으나, GUI를 기반으로 하는 웹 어플리케이션의 특성 때문에 사용자 관점에서 다양한 기능시험을 수행하기 위해서는 많은 노력과 시간이 필요하다. 특히 최근에는 과거와 달리 다양한 브라우저가 사용됨에 따라, 다양한 브라우저 상에서의 웹 어플리케이션 기능시험을 필수적으로 해야 하기 때문에 시험 수행 시간을 줄일 수 있는 시험방안이 절실히 요구되고 있다. 본 논문에서는 공개 소프트웨어인 GUI 시험 자동화 도구를 활용하고, 테스트 자동화를 위한 테스트 케이스를 생성하여 다수의 브라우저 환경에서 동시에 자동으로 기능시험을 수행할 수 있게 함으로써, 시험 효율성을 극대화하기 위한 웹 어플리케이션 시험 자동화 방안을 제안한다. 실제 사례적용을 통하여, 시험 시간을 획기적으로 단축시키고, 4개의 브라우저에 대하여 동시 시험 수행이 가능함을 확인하였다.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.324-337
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• 2010

For the development of load and resistance factor design, reliability analysis is required to calibrate resistance factors in the framework of reliability theory. The distribution of measured-to-predicted pile resistance ratio was constructed based on only the results of load tests conducted to failure for the assessment of uncertainty regarding pile resistance and used in the conventional reliability analysis. In other words, successful pile load test (piles resisted twice their design loads without failure) results were discarded, and therefore, were not reflected in the reliability analysis. In this paper, a new systematic method based on Bayesian theory is used to update reliability index of driven steel pile piles by adding more pile load test results, even not conducted to failure, into the prior distribution of pile resistance ratio. Fifty seven static pile load tests performed to failure in Korea were compiled for the construction of prior distribution of pile resistance ratio. Reliability analyses were performed using the updated distribution of pile resistance ratio and the total load distribution using First-order Reliability Method (FORM). The challenge of this study is that the distribution updates of pile resistance ratio are possible using the load test results even not conducted to failure, and that Bayesian update are most effective when limited data are available for reliability analysis or resistance factors calibration.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.3
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• pp.255-263
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• 2006

Vol-oxidizer is a device to convert $UO_2$ pellets into $U_3O_8$ powder and to feed a homogeneous powder into a Metal Conversion Reactor in the ACP(Advanced Spent Fuel Conditioning Process). In this paper, we propose a design model of the vol-oxidizer, develop the new vol-oxidizer with a capacity of 20 kg HM/batch in $UO_2$ pellets, and conduct a verification for the device. Design considerations include the internal structure, the capacity, the heating position of the device, and the size. The dimensions of the new vol-oxidizer are decided by the design model. We determine a permeability test of the $U_3O_8$ measuring the temperature distribution, and the volume of $UO_2$ and $U_3O_8$. We manufactured the new vol-oxidizer for a 20 kg HM/batch in $UO_2$ pellets, and then analyzed the characteristics of the $U_3O_8$ powder for the verification. The experimental results show that the permeability of the $U_3O_8$ throughout mesh enhance more than old vol-oxidizer, the oxidation time takes only 8 hours when compared with the 13 hours of the old device, and the average distribution of particle size is $40{\mu}m$. The capacities of new vol-oxidizer for a 20 kg HM/batch in $UO_2$ pellets were agree well with the predictions of design model.