• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.177-184
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• 2000

Geotube is a tube made of geotextile and hydraulically filled with dredged soil. This technological method has been widely used in the advanced countries of the world to build the shore protection embankment. The dredged contaminated sediments from the lake, river, and harbor can be pumped into the geotube by using the hydraulic pump. So, environments effects can be minimized and enhanced by using this method. This paper presents a field test result of a geotube in the land reclamation project for the Songdo New City construction site. The dredged silty clay was dredged by the dredging ship and hydraulically pumped into the geotube. The height of geotube was measured at every filling stage and also measured width and diameter of geotube with the elapsed time. The unit weight of soil and undrained shear strength of filled soil in a tube were measured at the various locations and heights of geotube with the elapsed time. Geotube technique can be effectively implemented for the silty clayey soil with using the dredging ship.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1167-1174
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• 2005

This paper describes on the volume change of Sewage Dredged Soils by using laboratory test and volumetric change test. The tremendous change of Moisture Content occured in the Sewage Dredged Soils during the Elapsed Time. The Unit Weight increases during the normally shrinkage limit void ratio and then the unit weight decrease. A volume of Sewage Dredged Soils according to the moisture content is a difference maximum 2.5 times. And there is the difference 3.5 times according to the change of unit weight. Therefore, the moisture content and unit weight computation are very important for the computation on the volume of Sewage Drdeged Soils.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.10a
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• pp.124-131
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• 1993

A successful site application with 700kg/$\textrm{cm}^2$ ultra-high strength concrete was made by research team of Daewoo Institute of Construction Technology in Jinhae. Trial mixings of concrete, the productivity of batcher plant, the elapsed time and the pumpability had been investigated for the site condition, before the site application. As results, the efficiency of production by automatic batcher plant systems was improved and the method of quality control was estabilished for the security of fluidity due to the elapsed time, the pumping and consolidation and so on. The concrete strength cores as well as cylinders was showed more than 700kg/$\textrm{cm}^2$ for the required age. And this study would be provided valuable data base for the practical utilization of high strength concrete. Further, this study would be given new possibilities of high rise RC constructions.

• Journal of Soil and Groundwater Environment
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• v.7 no.4
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• pp.3-9
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• 2002

In this study, electrokinetic remediation tests were performed with spiked fine-grained soil by phenanthrene which is representative hydrophobic organic contaminant of petroleum hydrocarbon. And also, the enhanced method was used with surfactant concentration variation and elapsed time to achieve more higher removal efficiency than conventional electrokinetic treatment. In conventional electrokinetic treatment, most phenanthrene was not transported. But, in the enhanced method used by the surfactant, phenanthrene moved form anode to cathode region and accumulated in cathode region. Also, the transportation rate of phenanthrene was increased with surfactant concentration increasement and elapsed time.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.61-62
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• 2021

Because of the problem of increasing self-weight due to the enlargement and high-rise of buildings using normal aggregate concrete, the need for structural lightweight aggregate concrete increases. However, early strength prediction is required when placing structural lightweight aggregate concrete, but research is insufficient. In this study, the ultrasonic pulse velocity of normal aggregate concrete and lightweight aggregate concrete was measured at early age. As a result, the ultrasonic pulse velocity of lightweight aggregate concrete was lower than normal aggregate concrete according to elapsed time at early age.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.409-410
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• 2023

In this study, the compressive strength and ultrasonic pulse velocity were evaluated according to the elapsed time on concrete mixed with normal and lightweight aggregates at early age. For evaluation in various strength ranges, the design compressive strength was set to 30, 45, and 60MPa and evaluated. As a result of the experiment, the compressive strength of concrete mixed with lightweight aggregates developed 5MPa earlier compared to normal aggregate concrete, and the UPV showed a similar tendency.

• Korean Journal of Cognitive Science
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• v.23 no.1
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• pp.73-95
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• 2012

Two experiments were conducted to verify how the factors of attentional dispersion, reason for waiting, and cue of time flow affect the perceived waiting time. In experiment 1, based on the characteristics of waiting experience that Maister(1985) suggested, levels of attentional dispersion and whether or not offering a reason for waiting were manipulated. Participants estimated elapsed time(the objective time was 10 minutes) using either prospective or retrospective estimation method. Overall results were that they overestimated the elapsed time regardless of the experimental conditions. However, both main effects of the attentional dispersion and the reason for waiting were statistically significant. That is, when attention was more dispersed and when the reason was given, overestimation of elapsed time was reduced. No difference was found between the two estimation methods, and none of the interaction was significant. Experiment 2 was a replication of Experiment 1 except that a cue of time flow was added by using scroll bar on a computer screen. Because it has been suggested that the cue can help us to manage the waiting time and result in differences between the two time estimation methods. The results showed that main effects of the attentional dispersion and the reason for waiting were significant as those in Experiment 1. In addition, main effect of time estimation method and the three-way interaction were also significant. None of two-way interaction was significant. That is, the perceived waiting time is much shorter in the retrospective method, and the effects of the attentional dispersion and the reason of waiting were dependent upon the estimation methods. Both experiments showed that offering a clear reason for waiting is more important than the attentional dispersion in reducing the perceived waiting time. Some implications of these results for the service industry and the future direction of research were discussed in the final section.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.18 no.2
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• pp.70-79
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• 2005

Background: Otitis media with effusion(OME) is one of the most common disease in childhood. Patient suffers from OME in many quarters. For example hearing loss, effects on speech, language, learning, behaviouralchanges etc. But the diagnosis of OME is difficult using only medical history and otoscopy. So, many other diagnostic tools are developed and tympanometry is one of them. When OME is treated by oriental medical Tx, tympanometry would be useful instrument. Objectives: To gain insight into the usability of tympanometry in F/U of OME treated by oriental medial Tx. Methods: Data was collected from 123 ears of 74 children who was treated by oriental medical Tx. Data includes sex, age, period of Tx, elapsed time to be improved, tympanograms and accompanied symptoms. The relationship between items was analysed by statistical methods. Results: There is no relationship between age, sex and period of Tx/elapsed time to be improved. When cough and phlegm is accompanied, the period of treatment and elapsed time to be improved are expanded. When improvement was seen on tympanogram, the period of treatment is expanded but the improvement was seen within 30days, the period of treatment is reduced. Conclusion: The application of tympanometry in oriental medical treatment of OME would provide us many informations about the status of patient so it will be helpful to predict the history of a case and to make a decision whether keep up treatment or not.

• Journal of the East Asian Society of Dietary Life
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• v.12 no.4
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• pp.289-298
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• 2002

This study was designed to investigate the anti-tumor effects of fresh carrot juice, methanol-extracts, and $\beta$-carotene on the human lung cancer cell line NCI-H1299. The anti-tumor effect was evaluated by the MTT assay in vitro. The anti-tumor effect of fresh carrot juice against NCI-H1299 lasted up to 96 hours after exposure; the viability rate of lung cancer cells decreased below 50% after 48 hours, and further after 72 hours. The strongest propagation inhibition effect of fresh carrot juice was shown at the concentration of 2000 $\mu\textrm{g}$/$m\ell$ after 72 hours and the viability rates was 45.98% even at the concentration of 25 $\mu\textrm{g}$/$m\ell$. The value of $IC_{50}$/ was 23.1$\mu\textrm{g}$/$m\ell$ when the elapsed time was 72 hours. The viability rate of methanol-extract was 52.4% under the concentration of 2000 $\mu\textrm{g}$/$m\ell$ and the elapsed time of 72 hours. Under the concentration of 1000 $\mu\textrm{g}$/$m\ell$ and the elapsed time of 48 hours, $\beta$ -carotene decreased the viability rate to 29.99%. The $IC_{50}$/ value of $\beta$-carotene was 691.2$\mu\textrm{g}$/$m\ell$ after 72 hours. According to the above results, the anti-tumor effect arose in NCI-H1299 when the concentration of the fresh carrot juice or the $\beta$-carotene was more than 25 $\mu\textrm{g}$/$m\ell$ or 1000 $\mu\textrm{g}$/$m\ell$, respectively. On the other hand, the methanol-extracts showed a weak anti-tumor effect even at a concentration as high as 2000 $\mu\textrm{g}$/$m\ell$.

• Tunnel and Underground Space
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• v.21 no.6
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• pp.460-470
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• 2011

Wave velocity was measured to define the weathering characteristics of rock and the strength evaluation of weathered rock on a target of the Aso gravestones with various sizes under the natural environment. As a result, the size correction method which was changed sample of the different size to one of the same size for evaluating wave velocity was proposed, and also suggested the NET (Normalized Elapsed Time) as a new weathering index of rock. In addition, the strength of the weathered rock was estimated from the weathering classification of rock using the NET. Wave velocity of welded tuff was high and didn't show velocity degradation, on the other hand, one of andesite was low and showed velocity degradation. The degree of weathering between rocks of the different size is considered to be comparable, applying the NET based on the on the $V_p/V_o$-NET curve. Furthermore, the classification of rock weathering stages using the NET based on the $S_c/S_o$-NET curve was available, and the estimation of strength for the weathered rock was also possible.