• Journal of the Korean Geosynthetics Society
• /
• v.17 no.3
• /
• pp.1-8
• /
• 2018

Sand compaction pile (SCP) is a ground improvement method which is used to secure the stability of the soft ground by using a type of replacement pile filled with coarse grained material. The behavior characteristics of the SCP, which is frequently used for improving both the onshore and offshore ground, is governed by the ground condition, the installation method, and replacement ratio. Therefore, the stability of the SCP in terms of the bearing capacity and displacement needs to be evaluated considering both the design values and in-situ conditions of construction site. In this study, numerical analysis is carried out based on the conditions of 00 revetment construction site in South Korea where unexpected displacement occurred during construction of SCP. Based on the analysis results, the displacement of the revetment structure according to the replacement ratio of the SCP was compared to the result calculated from design formulas. The results showed that the lateral displacement can be exceeded the reference value from proposed criteria regardless of increased replacement ratio of SPC. It is also confirmed that the behavior of the structure according to the replacement ratio of SPC in not reflected in the existing calculation methods. Therefore, the stability of the SCP composite ground should be examined through the site inspection after the SCP construction.

• Journal of the Korean GEO-environmental Society
• /
• v.13 no.3
• /
• pp.53-58
• /
• 2012

In general, sand compaction pile(SCP) method and gravel compaction pile(GCP) method have been mainly used to reinforce soft soils such as soft clay or loose sandy ground. But the sand compaction pile method has problems such as lack of sand supply and destroying the nature while collecting sand, the gravel compaction pile method has a problem such as decreased permeability of the drainage material due to clogging. Recently, the study to replace sand with bottom ash which has similar engineering properties with sand is in active. As a fundamental research on bottom ash mixture compaction pile utilizing bottom ash, its behavioral characteristics depending on granular materials and replacement ratio has been simulated numerically. In particular, Settlement Reduction Ratio(SRR) according to the distance from the center of pile was calculated. The main findings were as follows. Change values of Mixture Compaction Pile's SRR according to granular materials showed similar patterns and stiffness of the composite soil is increased depending on the replacement ratio so SRR showed decreased patterns. Especially, when the replacement ratio is in 20~40%, it increase significantly. When the replacement ratio is over 40%, it increase slowly. When considering the economics, 30~40% replacement ratio is appropriate.

• Journal of radiological science and technology
• /
• v.22 no.1
• /
• pp.21-26
• /
• 1999

To make a comparative analysis for clinical application of total hip replacement arthroplasty(THRA) using fluoroscopy, we have performed total hip replacement arthroplasty making 30 patients an object with general radiography and fluoroscopy respectively. The results are as follows : 1) Reexamination rate was 80% of patients and mean 3.9 sheets in the general radiography, where as it was 46.7% and 0.37 sheets in the fluoroscopy(p<0.01) 2) Add examination was 2 cases in the general radiography, but fluoroscopy was no add examination. 3) The total film sheet used was mean 10.16 in the general radiography and 6.73 in the fluoroscopy. 4) In the cause of reexmination and add examination, inaccurate position of patient accounted for 72.6% in the general radiography and poor exposure condition accounted for 45.5% in the fluoroscopy. Total hip replacement arthroplasty using the fluoroscopy decreased reexamination and add examination rate, for these reasons, this method was effective abatement of pain, exposured radiation dose, and examination time and so on.

• Journal of Korean Institute of Industrial Engineers
• /
• v.41 no.2
• /
• pp.150-161
• /
• 2015

This paper proposes a new approach to technology valuation, the market-replacement cost approach which integrates the cost-based approach and market-based approach. The proposed approach estimates the market-replacement cost of a target technology using R&D costs of similar R&D projects previously conducted. Similar R&D projects are extracted from project database based on document similarity between project proposals and technology description of the target technology. R&D costs of similar R&D projects are adjusted by mirroring the rate of technological obsolescence and inflation. Market-replacement cost of the technology is then derived by calculating the weighted average of adjusted costs and similarity values of similar R&D projects. A case of "Prevention method and system for the diffusion of mobile malicious code" is presented to illustrate the proposed approach.

• Journal of Chest Surgery
• /
• v.27 no.7
• /
• pp.581-586
• /
• 1994

From February 1985 to February 1993, 18 operations were performed in 17 patients for treatment of aneurysmal disease [n=12] and/or dissection of the ascending aorta [n=6]. The ages ranged from 26 to 69 years [mean 44.3 $\pm$ 11.0 years].The proposed operations include composite graft replacement of aortic valve and ascending aorta with coronary reimplantation in 11, graft replacement of ascending aorta alone in 5, aortic valve replacement and supracoronary graft replacement in 1 and ascending aorta to abdominal aorta bypass with thromboexclusion of descending aorta in one patient. Both Bentall [n=6] and Cabrol [n=5] technique were utilized for reimplantation of coronary arteries.Concomitant replacement of aortic arch and arch vessel reconstruction was necessary in two patients. Hypothermic circulatory arrest was utilized in 6 patients. Recently, four patients were managed on warm blood continuous cardioplegia via retrograde route. There were no operative deaths. No significant postoperative complications were noted. Postoperative follow up was complete in 15 patients from 1 month to 72 months. Redo operation was necessary in one patient who had suffered from distal recurrence of dissection 5 years after successful Bentall operation. The other patients are all in excellent clinical condition. From our early experience with those 17 cases, we assume that satisfactory operative result could be achieved with a variety of surgical technique including hypothermic circulatory arrest. In addition, continuous perfusion of warm blood cardioplegia via retrograde route is supposed to be beneficial in selected cases.

• Korean Journal of Adult Nursing
• /
• v.18 no.2
• /
• pp.183-193
• /
• 2006

Purpose: The purpose of the study was to test the effects of music therapy on postoperative pain in patients with total hip replacement. Method: The research design was a nonequivalent control group pretest-posttest design. The subjects were composed of thirty patients with total hip replacement. Fifteen of them were assigned to the experimental group and fifteen to the control group. Fifteen minutes tailored music therapy was given to the experimental group during five consecutive days. The instruments used for this study were pain NRS(numerical rating scale). The data were analyzed using percent, mean, standard deviation, ${\chi}^2-test$ and repeated measure ANOVA using SPSS WIN 11.0. Results: Hypothesis 1 "The score of pain NRS of experimental group will be lower than those of control group" was accepted(F=15.945, p<.001). Hypothesis 2 "The frequency of PCA analgesics of experimental group will be fewer than those of control group" was accepted (t=-2.312, p=.028). Hypothesis 3 "The vital signs(pulse, systolic BP and diastolic BP) of experimental group will be different from those of control group" was rejected. Conclusion: This music therapy can be recommended as an efficient nursing intervention to reduce postoperative pain in patients with total hip replacement.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2003.11a
• /
• pp.43-48
• /
• 2003

This paper investigate that the effect of the concrete containing mineral admixtures(pozzolanic materials such as fly-ash, ground granulated blast-furnace slag, silica fume and meta kaolin) on the resistance properties to chloride ion invasion. The purposed testing procedure was applied to the concrete added mineral admixtures for 3~4 replacement ratios under W/B ratios ranged from 0.40 to 0.55. For the electrical migration test, Tang and Nilsson's method was used to estimate the migration coefficient of chloride ion. As a results, the W/B ratios, kinds of admixture and replacement ratios, water curing periods had a great effect on the migration coefficient of chloride ion, and the optimal replacement ratios of admixture had a limitation for each admixtures. Also, the addition of mineral admixtures by mass(replacement of OPC) enhanced the resistance of the mixture to chloride penetration compared with the plain concrete. The amount of acid soluble chloride ions and water soluble chloride ions were varied with the kinds of mineral admixtures. The compressive strength was shown related to the migration coefficient of chloride ion, the compressive strength increased with the decreasing migration coefficient of chloride ion. Below the 50MPa, the variation of migration coefficient of concrete added mineral admixtures was bigger than plain concrete.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2003.05a
• /
• pp.43-48
• /
• 2003

This paper investigate that the effect of the concrete containing mineral admixtures(pozzaolanic materials such as fly-ash, ground granulated blast-furnace slag, silica fume and meta kaolin) on the resistance properties to chloride ion invasion. The purposed testing procedure was applied to the concrete added mineral admixtures for 3∼4 replacement ratios under W/B ratios ranged from 0.40 to 0.55. For the electrical migration test, Tang and Nilsson's method was used to estimate the migration coefficient of chloride ion. As a results, the W/B ratios, kinds of admixture and replacement ratios, water curing periods had a great effect on the migration coefficient of chloride ion, and the optimal replacement ratios of admixture had a limitation for each admixtures. Also, the addition of mineral admixtures by mass(replacement of OPC) enhanced the resistance of the mixture to chloride penetration compared with the plain concrete. The amount of acid soluble chloride ions and water soluble chloride ions were varied with the kinds of mineral admixtures. The compressive strength was shown related to the migration coefficient of chloride ion, the compressive strength increased with the decreasing migration coefficient of chloride ion. Below the 50MPa, the variation of migration coefficient of concrete added mineral admixtures was bigger than plain concrete.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2020.11a
• /
• pp.143-144
• /
• 2020

For modern people who spend 80% of the day indoors, indoor air quality is an important factor in their lives. Radon and fine dust, which are indoor air quality pollutants, cause various diseases and lung diseases, so a method is needed to reduce them. Therefore, this study intends to utilize the air pollutant adsorption properties of the carbonized sludge by using the carbonized sludge generated through drying and carbonization of the sludge. As a result of the experiment, it was shown that the concentration of radon and fine dust gradually decreased as the replacement ratio of carbonized sludge increased. The reason is that the carbonized sludge has the ability to adsorb fine dust and radon, so it is considered that it gradually decreases as the replacement ratio increases. Also, the compressive strength and flexural strength tend to decrease gradually. The reason for this is that the carbonized sludge has a number of internal voids, and as the replacement ratio increases, the internal voids increase and the strength decreases. If the refinement and strength of the carbonized sludge replacement ratio are supplemented, it is believed that it will be able to replace the existing finishing materials.

• Advances in concrete construction
• /
• v.16 no.6
• /
• pp.317-325
• /
• 2023

Strength prediction and correlation of concrete is done using experimental and analytical methods. Main objective is to correlate the experimental and simulated values of compressive strength of concrete mix using Fly Ash (FA) and Silica Fume (SF) by partial replacement of cement in concrete. Mix proportion was determined using IS method for M40grade concrete. Hundred and forty-seven cubes were cast and tested using Universal Testing Machine (UTM). Genetic Algorithm (GA) model was developed using C++ program to simulate the compressive strength of concrete for various proportions of FA and SF replacements individually at 3% increments. Experiments reveal that 12 percent silica fume replacement produced maximum compressive strength of 35.5 N/mm², 44.5 N/mm² and 54.8 N/mm² moreover 9 percent fly ash replacement produced a maximum strength of 31.9 N/mm², 37.6 N/mm² and 51.8 N/mm² during individual material replacement of concrete mix. Correlation coefficient for each curing period of fly ash and silica fume replaced mix were acquired using trend lines. The correlation coefficient is found to be approximately 0.9 in FA and SF replaced mix irrespective of the mix proportion and age of concrete. A higher and positive correlation was found between the experimental and simulated values irrespective of the curing period in all the replacements.