• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.75-76
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• 2017

In the case of B / a 1: 3, the intensity when the substitution rate increased to 15% showed a tendency to decrease, but it turned out that the strength increased at the substitution rate of 20%. In the case of B / a 1: 4 and 1: 5, it was found that when the substitution rate at the substitution rate of 10% was the highest and the substitution rate increased further, the strength was reduced. However, since the test body does not exist at the age of 3 days and the age of 7 days at the substitution rate of 0%, there is no specimen, so blast furnace slag binder substitution for increasing strength of refractory mortar is judged to be meaningless.

• Genomics & Informatics
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• v.16 no.1
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• pp.14-20
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• 2018

Despite the importance of mutation rate, some difficulties exist in estimating it. Next-generation sequencing (NGS) data yields large numbers of single-nucleotide polymorphisms, which can make it feasible to estimate substitution rates. The genetic substitution rates of Hanwoo and Holstein cattle were estimated using NGS data. Our main findings was to calculate the gene's substitution rates. Through estimation of genetic substitution rates, we found: diving region of altered substitution density exists. This region may indicate a boundary between protected and unprotected genes. The protected region is mainly associated with the gene ontology terms of regulatory genes. The genes that distinguish Hanwoo from Holstein in terms of substitution rate predominantly have gene ontology terms related to blood and circulatory system. This might imply that Hanwoo and Holstein evolved with dissimilar mutation rates and processes after domestication. The difference in meat quality between Hanwoo and Holstein could originate from differential evolution of the genes related to these blood and circulatory system ontology terms.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.1
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• pp.80-86
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• 2007

In this study we experimented setting time and basic properties as waste wood fiber and sodium silicate substitution rate to reuse waste wood fiber produced in construction field to wood chip board. To do this construction waste woods were crushed with the size less than 10mm, mixed with the rate of 1:2, 2.5, 3, and added sodium silicate with the rate of 0, 5% of cement content. The results are as follows. As the substitution rate of construction waste wood was increased delay of setting time was also increased, and the batch of adding 5% accelerator had a 13~17 hours faster setting time than non accelerator batch. The compressive strength was lower as wood substitution rate was higher, and as the specific gravity was higher, the strength was also higher. As wood substitution rate was higher, heat conductivity was lower, and as specific gravity was higher, heat conductivity also was higher.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.106-111
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• 2003

This paper is to investigate the characteristics of a concrete in which river sand is partially substituted with crushed sand. Since river sand has a relatively small fineness modulus, there is a need to increase the fineness modulus of sand used in the manufacture of concrete. In an experiment, it was observed that when river sand had a fineness modulus of 2.0~2.4 and crushed sand had a fineness modulus of 2.8~3.5, the substitution rate of the crushed sand was preferably within the range of 25~50%. The experimental results also revealed that as the substitution rate of the crushed sand increased, the flowability of the concrete tended to increase. However, when the substitution rate of the crushed sand reached 75% or more, the workability of the concrete was considerably poor. Further, as the substitution rate of the crushed sand increased, the air content and the bleeding rate of the concrete were low.

• Communications for Statistical Applications and Methods
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• v.27 no.4
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• pp.459-468
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• 2020

We examine the rate of substitution of jobs by artificial intelligence using a score called the "weighted ability rate of substitution (WARS)." WARS is a indicator that represents each job's potential for substitution by automation and digitalization. Since the conventional WARS is sensitive to the particular responses from the employees, we consider a robust version of the indicator. In this paper, we propose the individualized WARS, which is a modification of the conventional WARS, and compute robust averages and confidence intervals for inference. In addition, we use the clustering method to statistically classify jobs according to the proposed individualized WARS. The proposed method is applied to Korean job data, and proposed WARS are computed for five future years. Also, we observe that 747 jobs are well-clustered according to the substitution levels.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.207-214
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• 1997

Strength experimental on mortar which use Quenched Blast-Furnace Slag as aggregate was carried our for a fundamental study of application possibility of Quenched Blast-Furnace Slag as aggregate. It gives the following results. The strength of mortar use Quenched Blast-Furnace Slag is decrease as substitution rate is higher. As W/C rate increase, the strength decrease, but the strength decrease of fine aggregate rate 1:3 is lower than 1:2. The relation with fine aggregate is that the amount of fine aggregate is inversely proportional to strength. Th relation with age is proportional to strength and strength rate of going is lower than general mortar in 28 age the change of strength proportionately with W/C rate is that as W/C rate increases, th strength is drop ; it shows that it has same tendency as general mortar sand or crushed sand, but while W/C rate increase the strength is as high as general mortar. The reason can be assumed that water content per unit needed to Quenched Blast-Furance Slag is more than in case of sand. In addition, the relation with substitution rate is that the strength is the strongest at substitution rate 25% and 50% ; that is , sometimes it is higher than mortar which use sand 100%. In addition, long age strength of mortar which use Quenched Blast-Furnace Slag as aggregate is about to be studied in the last.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.40-45
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• 1999

This experimental study presents the strength properties of mortar using the blast-furnace slag sand. The mix disign of this study is based on the each three classes of unit water; (250, 275, 300)kg/㎥ and four classes of W/C; (45, 50, 55, 60)% and substitution rate(0, 25, 50, 75, 100)%. It gives following result. As W/C ratio increase, the strength is decrease. In case of mortar using air-cooled blast-furnace slag sand, the 3-days and 7-days compression strength is increase as substitution rate is higher. But in case of the mortar using the quenched blast-furnace slag sand, the compression strength is decrease as substitution rate is higher.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.215-222
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• 1997

Flow experimental on not to be solid mortar which use Quenched Blast-furnace Slag as a fine aggregate was carried out for basic research data about fundamental study of application possibility of Quenched Blast-furnace Slag as a fine aggregate. It gives following result. The substitution rate is inversely proportional to Flow and C/S-rate same that. The relation with W/C-rate augment appear proportional : in case of C/S-rate, 1:3 increasing degree is a half of sand mortar that. Consequencely, Quenched Blast-furnace Slag motar is a counteraction to Flow in as same water content per unit. But suitable substitution rate and C/S-rate influence a little to the mortar consistency. And that reason, if C/S-rate and substitution rate will be regulated when we mix the mortar with quenched Blast-furnace Slag. that will be economic mixture.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.1
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• pp.131-138
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• 2010

This research intends to analyze the basic characteristics of cements(hereinafter "CC") with affordable price and particle distribution effective as hydration heat face which are discharged at the outlet of smashing process of ordinary portland cement(hereinafter "OPC") manufacturing process such as fluidity, rigidity, temporary insulation temperature increase amount etc to review the potential of developing "CC" to 3 ingredients low heat cement that substitutes fly ash and blast furnace slag(hereinafter "BS"). As a result of experiment, fluidity tended to decrease with increase in CC substitution rate, and increase with increase in FA+BS substitution rate. Air amount tended to slightly decrease with increase in CC substitution rate, and decrease with increase in FA+BS substitution rate. Condensation characteristics were such that condensation time was delayed with increase in CC and FA+BS substitution rate. As for the temperature rising amount by temporary insulation, peak temperature decreased with increase in CC substitution rate and increase in FA+BS substitution rate in general, and thereafter, temperature tended to decrease slowly. Compressive strength decreased with increase in CC and FA+BS substitution rate, and as aging goes on, long term strength was equivalent to plain or higher. By and large, when FA+BS was substituted to CC, fluidity and air amount tended to decrease, but hydration heat face showed good reduction effects, suggesting possibility of development to 3 ingredients low heat cement.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.143-144
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• 2015

In this research it was attempted to analyze the general engineering properties of low cement mortar according to the type of setting accelerator and substitution rate, when 1% substitution rate for setting accelerator was used a high rate of compressive strength manifestation was shown and that the WS-10 type setting accelerator was appropriate. For the rate of change of length, when 3% substitution rate for setting accelerator was used, it was shown that due to initial expansion the shrinkage compensation was not significant, and when taking into consideration strength and shrinkage, 1% of WS-10 was shown to be appropriate.