• Korean Journal of Radiology
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• v.25 no.7
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• pp.634-643
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• 2024

Objective: This study aimed to evaluate the diagnostic efficacy and safety of low-contrast-dose, dual-source dual-energy CT before transcatheter aortic valve replacement (TAVR) in patients with compromised renal function. Materials and Methods: A total of 54 consecutive patients (female:male, 26:38; 81.9 ± 7.3 years) with reduced renal function underwent pre-TAVR dual-energy CT with a 30-mL contrast agent between June 2022 and March 2023. Monochromatic (40- and 50-keV) and conventional (120-kVp) images were reconstructed and analyzed. The subjective quality score, vascular attenuation, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) were compared among the imaging techniques using the Friedman test and post-hoc analysis. Interobserver reliability for aortic annular measurement was assessed using the intraclass correlation coefficient (ICC) and Bland-Altman analysis. The procedural outcomes and incidence of post-contrast acute kidney injury (AKI) were assessed. Results: Monochromatic images achieved diagnostic quality in all patients. The 50-keV images achieved superior vascular attenuation and CNR (P < 0.001 in all) while maintaining a similar SNR compared to conventional CT. For aortic annular measurement, the 50-keV images showed higher interobserver reliability compared to conventional CT: ICC, 0.98 vs. 0.90 for area and 0.97 vs. 0.95 for perimeter; 95% limits of agreement width, 0.63 cm² vs. 0.92 cm² for area and 5.78 mm vs. 8.50 mm for perimeter. The size of the implanted device matched CT-measured values in all patients, achieving a procedural success rate of 92.6%. No patient experienced a serum creatinine increase of ≥ 1.5 times baseline in the 48-72 hours following CT. However, one patient had a procedural delay due to gradual renal function deterioration. Conclusion: Low-contrast-dose imaging with 50-keV reconstruction enables precise pre-TAVR evaluation with improved image quality and minimal risk of post-contrast AKI. This approach may be an effective and safe option for pre-TAVR evaluation in patients with compromised renal function.

• Journal of the Society of Disaster Information
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• v.18 no.1
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• pp.104-115
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• 2022

Purpose: Infrastructure inspection and its diagnostics technique have been rapidly developing recently. Therefore, it is important to secure the reliability of diagnostic equipment, and this paper deals with inspection of diagnostic equipment, introduction to a certification system and development plans for infrastructure. Method: Several certification systems are established and introduction plans are reviewed through experts by synthesizing the contents of certification research for existing infrastructure diagnosis equipment. In addition, the revision of the law for introduction of the system is reviewed, detailed operation regulations are prepared and phased development plans are reviewed, which are based on the operation scenario. Result: Inspection and certification plans were constructed through four routes in order to consider infrastructure inspection and diagnostic equipment in use, and new diagnostic equipment using state-of-the-art technology. Furthermore, market confusion depending on the introduction of a new certification system is minimized and reliability is secured by transforming a simple inspection system in the short term into a formal certification system in the long term. The law amendments according to the introduction of the system were reviewed and detailed operation regulations were developed. Also, phased development plans, which are based on the long-term development scenario including manpower, infrastructure and specifications, were presented. Conclusion: It is important to secure reliability through the distribution and certification of diagnostic equipment using 4th industrial technology to strengthen the safety management of infrastructure at the national level since the infrastructure is various in type and increasingly large in size. It is also essential to train human resources who can use new technology with inspection and diagnosis system in order to enhance the safety management of all infrastructures. Moreover, it is necessary to introduce a regular inspection system for infrastructure that combines loT technology in the long-term point of view and to promote the introduction by giving active incentives to institutions that actively accept it.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.33-39
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• 2006

Home modification has come to be recognized as an important intervention strategy to manage health care conditions, maintain or improve functioning, ensure safety, and reduce the wheelchair user's dependency on others. However, the availability of skilled professionals with experience in home modifications for accessibility is limited. A system that enables accurate remote assessments would be an important tool to improve our ability to perform home assessments more easily and at decreased cost. A Remote Wheelchair Accessibility Assessment System (RWAAS) using Virtualized Reality(VR) technology was developed that enabled clinicians to assess the wheelchair accessibility of users' built environments from a remote location. Characteristics of the camera and 3D reconstruction program chosen for the system significantly affect its overall reliability. In this study, we performed two reliability analyses on the hardware and software components: 1) Verification that commercial software can construct sufficiently accurate 3D models by analyzing the accuracy of dimensional measurements in a virtualized environment; 2) comparison of dimensional measurements with four camera settings. Based on these two analyses, we were able to specify a consumer level digital camera and the Photomodeler Pro software for this system. And we then tested the feasibility of the selected software and hardware in an actual environment. Lastly, A field evaluation was performed to test whether this new system is comparable to the traditional method of accessibility assessment to evaluate its ability to assess the accessibility of a wheelchair user's typical built environment. The results of field trials showed high congruence between the assessments by two methods. Findings suggested that the RWAAS assessments have the potential to enable specialists to assess potential accessibility problems in built environments regardless of the location of the client, home, or specialist.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.595-601
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• 2020

During the safety inspection of nitrocellulose-made explosive containers stored for more than 10 years, cracks were found in the containers. Therefore, a failure cause analysis test was performed. First, the cause of failure through the failure tree analysis was conducted to select the factors that influenced failure. The changes in the properties of the container caused by the acceleration of the reaction were found to be the cause of the failure by confirming the influence on the environment and internal/external factors that may occur during storage. To confirm this, environmental tests, such as thermal shock test and vacuum thermal stability test, were performed using a naturally aged container to analyze the cause of failure, and an accelerated aging test was performed to reproduce the failure. Through this, the chemical reaction was accelerated by heat and charge, as in the result of the fault tree analysis, and it was confirmed that the physical properties of the container were changed. In addition, the service life of the container was estimated using the Arrhenius model for the storage life due to thermal aging.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.765-768
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• 2007

In this paper, the security evaluation method about mobile web services message is suggested in the method for improving the safety an reliability about the mobile web services message. In order that the goal of this paper is accomplished, the security threat and the security vulnerability which can be occurred in the mobile web services message are defined. The evaluation method for performing the security evaluation about the mobile web services message is defined. Also, the requirements for the mobile web services message security evaluation are defined. Finally, the evaluation framework for performing the mobile web services message security evaluation is constituted, and the evaluation scenario example is suggested. By using the mobile web services message security evaluation defined in the paper, before the mobile web services is deployed, the security threats and security vulnerability can be verified. Also, the countermeasure for the security threat and security vulnerability discovered in the verification result can be prepared. Therefore, the sorority and reliability about the mobile web services can be improved.

• Journal of the Korea Concrete Institute
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• v.17 no.3 s.87
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• pp.313-322
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• 2005

Recently, as the remodeling market gradually substitute for new construction market and safety diagnosis for reconstruction apartment become a matter of principal Interest, it is demanded that scientific diagnosis and evaluation for existing concrete structure state. And it is increasing that the significance for reliability of data which is used for estimating the concrete compressive strength by nondestructive test. As a result, it is found that different proposal to material age and hitting angle is good to improving the reliability of presumption of concrete compressive strength in the linear hitting rebound test hammer. And for the reason that mutual relation between the compressive strength and rebound degree is highest in linear hitting rebound test hammer 25mm in all portion according to early md middle material age and hitting angle except the early material age $-45^{\circ}$, analysis showed that linear hitting rebound test hammer is more reliable than existing schmidt hammer in presumption of concrete compressive strength.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.2
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• pp.77-85
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• 2009

In South Korea, seasonal, local and temporal climatic characteristics are variable in rainfall patterns. To design or assess the reliability of hydrosystem, information about the rainfall event under consideration is important. In this process, the complete description of a design storm involves the specification of rainfall duration, depth, and its temporal pattern. Generally, to use an appropriate temporal pattern for a design storm is of great importance in the design and evaluation of hydrological safety for hydrosystem. For purpose of selecting of factors affecting the occurrence of rainfall patterns, Huff's dimensionless method was executed and examined by statistical contingency tables analysis through which the inter-dependence of the occurrence frequency of rainfall patterns with respect to geographical location, rainfall duration and depth, and seasonality is investigated. This analysis result can be used to establish flood policies and to design or assess the reliability of hydrosystem.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.303-306
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• 2011

Although PV module manufacturing and its structure are simple, the semi-permanent products can be used out doors for more than twenty years. Therefore it is need to choose proper materials and optimize manufacturing process. This paper suggest that factors of degradation need to be studied to achieve a more understanding of PV module Degradation rates and material failure. Nowadays durability of the PV Module is very important to sustain output safety for obtaining reliability. This paper is about the experiment that soldering uniformity of soldering process and to make least void from soldering process. From This study soldering flux residue and soldering method is main factor to form void blocked soldering uniformity and by using this.

• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.4
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• pp.339-344
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• 2007

Safety of large scale cable in bridge is very important because it may cause the unwanted catastrophic failure. Although the proof load were considered at the design stage, its soundness must be monitored continuously because the cable may be broken out without warning by the variable external load. The cable tension of in-use structures has been mainly measured by the resonance method and its use has been limited because of relatively large measurement uncertainty. Recently a new magnetic method was developed and its reliability is known to be good for evaluating the cable tension. In this study a system which can deliver the calibrated load to the cable was developed and the measurement reliability of developed magnetic sensor according to the change of external load was analyzed quantitatively. The effect of magnetization frequency, bias magnetic field, and temperature on the sensor output was also evaluated.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.18 no.2
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• pp.87-100
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• 2022

Unit capacity factor (utilization rate) of nuclear power plants (NPPs) is an important performance indicator. Since the first commercial operation of Kori Unit 1 began in April 1978, the utilization rate of domestic NPPs has gradually increased, reaching 90% from the end of the 1990s. However, due to various issues such as the Fukushima accident in 2011, corrosion of the CLP, the utilization rate dropped to 65~80%. In the early 1980s, the utilization rate of the U.S. NPPs was around 60%. However, since 2004, it has been consistently maintained above 90%. Therefore, in this study, we first examined the causes of declining the utilization rate in domestic NPPs. Next, the significances of the utilization rates are reviewed in five aspects: investment capability, electricity rate, safety and export, etc., with discussion on the current status of the utilization rates in the U.S. Based on this, three key factors are derived as the reasons of the increasing: equipment reliability program, on-line maintenance and the pursuit of institutional rationality. And finally, by synthesizing above results, the measures for increasing the utilization rate of domestic NPPs are proposed in terms of equipment management, institutional improvements, and personnel resources.