• Advances in concrete construction
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• v.10 no.6
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• pp.537-546
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• 2020

Exterior walls in buildings are exposed to various forms of thermal loads, which depend on the positions of walls. Therefore, one of the efficient methods for improving the energy competence of buildings is improving the thermal properties of insulation plaster mortar. In this study, lightweight fine aggregate (LWFA) and micro rubber ash (MRA) from recycled tires were used as partial replacements for sand. The flow ability, unit weight, compressive strength, tensile strength, thermal conductivity (K-value), drying shrinkage and microstructure scan of lightweight rubberized mortar (LWRM) were investigated. Ten mixtures of LWRM were prepared as follows: traditional cement mortar (control mixture); three mixes with different percentages of LWFA (25%, 50% and 75%); three mixes with different percentages of MRA (2.5%, 5% and 7.5%); and three mixes consisting both types with determined ratios (25% LWFA+5% MRA, 50% LWFA+5% MRA and 75% LWFA+5% MRA). The flow ability of the mortars was 22±2 cm, and LWRM contained LWFA and MRA. The compressive and tensile strength decreased by approximately 64% and 57%, respectively, when 75% LWFA was used compared with those when the control mix was used. The compressive and tensile strength decreased when 5% MRA was used. By contrast, mixes with determined ratios of LWFA and MRA affected reduced unit weight, K-value and dry shrinkage.

• The Journal of Industrial Distribution & Business
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• v.11 no.2
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• pp.25-31
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• 2020

Purpose: The AEO (Authorized Economic Operator) program, created in 2001 in the United States due to 9.11 terrorist's attack, fundamentally changed the trade environment. Korea, which introduced AEO program in 2009, has become one of the world's top countries in the program by ranking 6th in the number of AEO certified companies and the world's No. 1 in MRA (Mutual Recognition Agreement) conclusions. In this paper, we examined what trade-economic and non-economic effects the AEO program and its MRA have in Korea. Research design, data and methodology: In this study we developed a model to verify the impact between utilization of AEO and trade-economic effects of the AEO and its MRA. After analyzing the validity and reliability of the model through Structural Equation Model we conducted a survey to request AEO companies to respond their experience on the effects of AEO program and MRA. As a result, 196 responses were received from 176 AEO companies and utilized in the analysis. Results: With regard to economic effects, the AEO program and the MRA have not been directly linked to financial performance, such as increased sales, increased export and import volumes, reduced management costs, and increased operating profit margins. However, it was analyzed that the positive effects of supply chain management were evident, such as strengthening self-security, monitoring and evaluating risks regularly, strengthening cooperation with trading companies, enhancing cargo tracking capabilities, and reducing the time required for export and import. Conclusions: When it comes to the trade-economic effects of AEO program and its MRA, AEO companies did not satisfy with direct effects, such as increased sales and volume of imports and exports, reduced logistics costs. However, non-economic effects, such as reduced time in customs clearance, freight tracking capability, enhanced security in supply chain are still appears to be big for them. In a rapidly changing trade environment the AEO and MRA are still useful. Therefore the government needs to encourage non-AEO companies to join the AEO program, expand MRA conclusion with AEO adopted countries especially developing ones and help AEO companies make good use of AEO and MRA.

• Journal of the Korean Society of Radiology
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• v.15 no.3
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• pp.281-291
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• 2021

This study aimed to measure the quantitative changes in images according to the use of compressed sensing in expressing the slow flow rate in TOF MRA test using magnetic resonance imaging. This study set different blood flow rate sections by using auto-injector and flow phantom and compared changes in the SNR, CNR, SSIM, and RMSE measurements by different CS factors between TOF with CS and TOF without CS. One-way ANOVA was performed to test the effect on the image induced by the increase of the CS factor. The results revealed that TOF MRA with CS significantly decreased scan time without significantly affecting SNR and CNR compared to TOF MRA with CS. On the other hand, the differences in SSIM and RMSE between TOF with CS and TOF without CS increased as the CS factor increased. Therefore, it is necessary to efficiently reduce scan time by adapting the CS technique while considering the appropriate range of the CS factor. Additionally, more studies are needed to evaluate CS factors and the similarity precision of images further.

• Investigative Magnetic Resonance Imaging
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• v.11 no.1
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• pp.33-38
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• 2007

Purpose : To investigate the applicability of the new three-dimensional overlapped reconstruction MR angiography (3-D ORMRA) technique in patients with hemifacial spasm and to compare the new 3-D reconstruction images with conventional MRA source images. Materials and Methods : The study group comprised 27 patients with surgically proven hemifacial spasm. In all patients, conventional MRA source images and 3-D fast imaging employing steady-state acquisition (FIESTA) images were obtained prospectively. After 3-D MR angiographic images were obtained, the 3-D MRA and FIESTA images were overlapped at the workstation by using GE A/W 4.2 add/sub software. We analyzed the relationship between the offending vessels and root exit zone of the facial nerve using both 3-D ORMRA images and conventional MRA source images. Results : In 25 of 27 patients, the offending vessel at the REZ of the facial nerve could be correctly identified on conventional MRA source images. In all patients, the presumed offending vessels depicted by the overlapped 3-D reconstruction MRA image corresponded well with the intraoperative findings. The 3-D reconstruction image showed more clear visualization of the spatial relationship between the offending vessels and the root exit zone of the facial nerve. Conclusion : The overlapped 3-D reconstruction MR angiography technique is very useful and informative in patients with hemifacial spasm, as compared with conventional MRA angiography technique.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.131-134
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• 2007

From January 2000 to September 2006, we use the 81 months of the data to estimate the exportation and importation function of the Korea information communications main device industry towards to U.S., and through this process we extract the cost elasticity. And from cost elsticity, we estimate the exportation and importation enlarging effect between Korea and U.S assumption of the exportation and importation reduction rate was givien to MRA contract between Korea and U.S.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.73-76
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• 1996

Computer simulation and magnetic resonance angiograms(MRAs) are used to understand for flow patterns in the carotid arterial bifurcation. Steady momentum equation is solved by the finite volume method. A Phantom of the carotid artery made of bioacrylic material is used for MRA observation. Flow Patterns are observed by using MRA for flow in the phantom of an automatic closed-type circulatory system filled with sugar 4 w% solution. For numerical analysis the idealized geometric shape of the carotid artery is constructed to portray the phantom. Results of numerical analysis are compared with those of MRA. The flow patterns of the phantom on MRA are almost identical to those of the computer simulation.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.1
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• pp.54-62
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• 1995

This paper is a study on a speed control of an induction motor used the MRA-DSM(Mode1 Reference Adaptive-Discrete Sliding Mode) controller. In this paper, when controls motor speed, DSM algorithm is proposed for having Robustness against disturbance and parameter variation. and it is also proposed MRA-DSM including the additional load model reference algorithm, which can be compensated the discontinuous control imputs at sliding mode and followed the model Preference independent of parameter variation of control subjects. The control system is composed of the parallel processing control system using the microprocessor for maximizing the performance of control systems and the real time processing. Also it simplifies the hardware composed of controlling the system by software and improves the reliability of the system. And while MRA-DSM control, faster response characteristics of 27.2 % is obtained than DSM control.

• Journal of the Korean Magnetic Resonance Society
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• v.20 no.2
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• pp.36-40
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• 2016

MRA1997 is a highly conserved protein from mycobacterial strains. However, no structural and functional information is associated with it. Thus, to obtain details about structure and function of this protein, we have utilized NMR spectroscopy. The recombinant MRA1997 was highly purified and its DNA binding mode was characterized. The tertiary structure of MRA1997 was modeled on the basis of our NMR chemical shift data combined with the webserver CS23D. The binding of MRA1997 with DNA was first monitored by electrophoresis mobility shift assays. The residues involved in DNA binding are identified using NMR chemical shift perturbation experiments. Based on our study, we suggest that MRA1997 interacts with DNA and may play an important role in Mycobacterium tuberculosis physiology.

• Journal of the Korean Magnetic Resonance Society
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• v.19 no.1
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• pp.49-53
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• 2015

MRA1997 is a 76-residue conserved hypothetical protein of Mycobacterium tuberculosis H37Ra, one of the most pathogenic bacterial species and the causative agent of tuberculosis. In this study, the sequence-specific backbone resonance assignment of MRA1997 was performed using NMR spectroscopy. Approximately 88.3% of the total resonances could be unambiguously assigned. By analyzing deviations of the $C{\alpha}$ and $C{\beta}$ chemical shift values, the secondary structure of MRA1997 was calculated. The result revealed that secondary structure of MRA 1997 consists of one ${\alpha}$-helix and five ${\beta}$-sheets. Our structural study will be a footstone towards the characterization of the three-dimensional structure of MRA1997.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.637-645
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• 2017

The objective of this study was to find the optimum test device for the cerebral blood vessels by comparing and analyzing the SNR and CNR methods for images of three devices (i.e., MRA, CTA, and DSA). The study targeted 90 patients who underwent cerebral angiography from November 2016 to May 2017. The measuring parts were measured by using Rt MCA, Lt MCA, and ACA Image J. The results of quantitative analysis showed that the mean SNR of MRA, the CNR of MRA, the signal strength of MRA, the mean SNR of CTA, the CNR of CTA, the signal strength of CTA, the SNR of DSA, the CNR of DSA, and the signal strength of DSA were evaluated as 254.87, 178.13, 326.81, 74.75, 62.2, 356.66, 26.85, 25.89, and 4400.69, respectively (p<0.05). As a result, both SNR and CNR methods measured it in the order of MRA>CTA>DSA. Statistical significance was determined by using ANOVA analysis at p<0.05 and Bonferroni method was used as a post-hoc analysis SPSS. In conclusion, the results of this study revealed that the optimum imaging devices were MRA, CTA, and DSA after evaluating randomly selected patients with cerebrovascular disease.