• Smart Structures and Systems
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• v.29 no.3
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• pp.433-444
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• 2022

Concrete is a most utilized material in the construction industry that have main components. The strength of concrete can be improved by adding some admixtures. Evaluating the impact of fly ash (FA) and silica fume (SF) on the long-term compressive strength (CS) of concrete provokes to find the significant parameters in predicting the CS, which could be useful in the practical works and would be extensible in the future analysis. In this study, to evaluate the effective parameters in predicting the CS of concrete containing admixtures in the long-term and present a fitted equation, the multivariate adaptive regression splines (MARS) method has been used, which could find a relationship between independent and dependent variables. Next, for optimizing the output equation, biogeography-based optimization (BBO), particle swarm optimization (PSO), and hybrid PSOBBO methods have been utilized to find the most optimal conclusions. It could be concluded that for CS predictions in the long-term, all proposed models have the coefficient of determination (R²) larger than 0.9243. Furthermore, MARS-PSOBBO could be offered as the best model to predict CS between three hybrid algorithms accurately.

• Structural Engineering and Mechanics
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• v.86 no.2
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• pp.181-195
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• 2023

To predict the rheological behaviours along with the compressive strength of self-compacting concrete that incorporates environmentally friendly ingredients as cement substitutes, a comparative evaluation of machine learning methods is conducted. To model four parameters, slump flow diameter, L-box ratio, V-funnel time, as well as compressive strength at 28 days-a complete mix design dataset from available pieces of literature is gathered and used to construct the suggested machine learning standards, SVM, MARS, and Mp5-MT. Six input variables-the amount of binder, the percentage of SCMs, the proportion of water to the binder, the amount of fine and coarse aggregates, and the amount of superplasticizer are grouped in a particular pattern. For optimizing the hyper-parameters of the MARS model with the lowest possible prediction error, a gravitational search algorithm (GSA) is required. In terms of the correlation coefficient for modelling slump flow diameter, L-box ratio, V-funnel duration, and compressive strength, the prediction results showed that MARS combined with GSA could improve the accuracy of the solo MARS model with 1.35%, 11.1%, 2.3%, as well as 1.07%. By contrast, Mp5-MT often demonstrates greater identification capability and more accurate prediction in comparison to MARS-GSA, and it may be regarded as an efficient approach to forecasting the rheological behaviors and compressive strength of SCC in infrastructure practice.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.447-449
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• 1998

본 논문에서는 ATM망에서 IP멀티캐스트를 지원하기 위한 방법을 소개하고. 이를 바탕으로 좀더 효율적으로 IP 멀티캐스트를 지원하기 위한 방법을 제안하였다. Intra-cluster 멀티캐스트에 기반을 둔 MARS 모델은 IP멀티캐스트를 효율적으로 지원하지 못하며, 전체 망을 하나의 서버로 관리하는 EARTH 모델은 모든 처리가 서버로 집중되어 확장성 및 관리에 어려움이 있다. 본 논문은 효율적인 데이터 전송이 가능하면서 동시에 확장이 용이하도록 MARS 프로토콜을 확장하였다.

• Journal of the Korean Society of Safety
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• v.27 no.5
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• pp.229-234
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• 2012

Operator's action time is evaluated from MAAP4 analysis used in conventional probabilistic safety assessment(PSA) of a nuclear power plant. MAAP4 code which was developed for severe accident analysis is too conservative to perform a realistic PSA. A best-estimate code such as RELAP5/MOD3, MARS has been used to reduce the conservatism of thermal hydraulic analysis. In this study, operator's action time of core cooling recovery operation is evaluated by using the MARS code, which its Fussell-Vessely(F-V) value was evaluated as highly important in a small break loss of coolant(SBLOCA) event and loss of component cooling water(LOCCW) event in previous PSA. The main conclusions were elicited : (1) MARS analysis provides larger time window for operator's action time than MAAP4 analysis and gives the more realistic time window in PSA (2) Sufficient operator's action time can reduce human error probability and core damage frequency in PSA.

• Nuclear Engineering and Technology
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• v.41 no.3
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• pp.295-306
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• 2009

The subchannel grade void distributions in the NUPEC (Nuclear Power Engineering Corporation) BFBT (BWR Full-Size Fine-Mesh Bundle Tests) facility were evaluated with the subchannel analysis code MATRA and the system code MARS. Fifteen test series from five different test bundles were selected for an analysis of the steady-state subchannel void distributions. Two transient cases, a turbine trip without a bypass as a typical power transient and a re-circulation pump trip as a flow transient, were also chosen for this analysis. It was found that the steady-state void distributions calculated by both the MATRA and MARS codes coincided well with the measured data in the range of thermodynamic qualities from 5% to 25%. The results of the transient calculations were also similar and were highly feasible. However, the computational aspects of the two codes were clearly different.

• Journal of Astronomy and Space Sciences
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• v.39 no.4
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• pp.141-144
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• 2022

By providing an environment where energetic particles and micrometeorites can not penetrate, caves on Mars may serve as a human shelter in future Mars explorations. More than 1,000 cave entrance candidates have been detected; however, their physical characteristics that can be utilized in detecting more candidates have not been explored in detail. In this paper, we explore the nighttime temperature of 100 cave entrance candidates and their surrounding areas to investigate 1) the nighttime temperature tendencies relative to their surrounding areas and 2) the extent of these temperature differences. We find that 79% of the cave entrance candidates exhibit higher temperatures than the surrounding areas, and 59% show a temperature difference over 20K, suggesting that the cave entrances may generally show higher temperatures than the surrounding areas during the nighttime.

• Proceedings of the Korean Nuclear Society Conference
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• 2001.05a
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• pp.237.1-237
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• 2001

• Proceedings of the Korean Nuclear Society Conference
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• 2001.05a
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• pp.169.1-169
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• 2001

• Proceedings of the Korean Nuclear Society Conference
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• 2003.05a
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• pp.180-180
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• 2003

• Proceedings of the Korean Nuclear Society Conference
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• 1999.05a
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• pp.144-144
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• 1999