• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.1-11
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• 2021

As the aging of large domestic SOC facilities accelerates, facility maintenance is also changing from safety evaluation based on the current condition to performance-oriented preventive and preemptive maintenance based on the prediction of the level of future obsolescence. In particular, in the case of bridges, class 1 and 2 bridges are systematically managed along with many studies, but for small and medium-sized class 3 bridges there is no collection and utilization of historical data presenting performance degradation during their service life. Therefore, in this study, 3D model-based demonstration DB system was designed and developed to intuitively check the damage change rate at the damage location by registering the maintenance history by life cycle for each member's exterior damage in the 3D bridge object and to enable API-based comprehensive performance evaluation.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.1146-1153
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• 2022

As the population is aging, accidents involving elderly people are also increasing (2014:11,667 persons; 2018: 11,797 persons). In the case of the elderly population, falling accidents are the primary direct or indirect causes of death; in particular, they face an elevated risk of staircase falls. This study proposes a method of evaluating the safety of staircases using Building Information Modeling (BIM)-based virtual simulation. By making a virtual user with the behavioral characteristics of the elderly respond to a staircase in a BIM model, its safety performance can be evaluated. The evaluation criteria were derived from regulations, elements, and characteristics relevant to the safety of staircases. To validate the proposed method, safety evaluation tests were simulated on actual staircases. The evaluation result of the test simulation shows the safety scores of 1.97 points for the elderly user and 2.95 points for the average male adult user against a required safety score of a minimum of 2 points. That is, safety is relative to users as the safety of the same staircase can be different depending upon the different behavioral characteristics of users. The study suggests that the risk of staircase-related fall accidents to the elderly can be reduced by improving staircase designs through the proposed method.

• The KIPS Transactions:PartB
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• v.14B no.6
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• pp.407-412
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• 2007

The performance of ultrasonic testing systems for industrial or medical purpose largely depends on the performance of ultrasonic transducers. Generally, the information about an ultrasonic transducer performance characteristics are expressed by the ultrasonic R/F signal back from a reflector and its frequency characteristics in the data sheet provided by manufacturers. In case of focused ultrasonic transducers, the two pieces of information can, however, hardly assure that the focused ultrasonic transducer would produce well-focused C-scan images. Therefore, we propose the measured size of focal spot and the reconstructed shape of effective focal zone in the focused sound field as novel measures for the performance evaluation of the focused ultrasonic transducers. The process of getting the both measures of the transducers is conducted by the implemented software including sound field scanning and virtual 3D reconstruction functions which requires the echo of a point reflector. The proposed method could, otherwise impossible in the existing method, effectively and simply distinguish superior ones among many transducers made in the same specification and be also used to detect the performance degradation due to the aging of the transducers. Eventually, the quality of performance of the ultrasonic testing systems for industrial or medical purpose is secured.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.109-114
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• 2000

Recently, it is required to improve the structural performance, such as durability and earthquake resistant capacity due to the deterioration of structural components in the existing reinforced concrete building with the old aging and transition of design code. Therefore, the new technology should be developed, such as seismic retrofit and improvement of structural performance in the existing reinforced concrete building. This analytical study was performed to verify the effects of basic and reinforcing system in the reinforced concrete building. The analytical results by nonlinear finite element method were compared with the experimental results and the comparisons are judged to be good.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.321-324
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• 2006

The latest concrete has showed that the deterioration of durability has been increased by the damage from salt, carbonation, freezing & thawing and the others. Therefore, it is needed to protect durability and performance according to the appropriate materials and methods in the concrete structures. In general, several types of polymer and silicate are used as protecting deterioration agents of concrete structures, but these agents have many problems because of low durability and properties. In this study, It developed the deterioration restraining agent using polycondensed silicate and monomer that can block a deterioration cause such as CO2 gas, salt and water from the outside and enhance waterproofing ability by reinforcing the concrete surface when applying it to concrete structures. Also, it evaluated improving concrete performance using a deterioration restraining agent.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.2
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• pp.59-68
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• 1996

In this paper, we propose two types of WDMA protocol for multi-wavelength optical networks that have a dedicated control channel. Protocol type I is designed for the case that the number of nimislots is less than the number of nodes (La${\ge}$M). Proposed protocols employ the aging scheme to guarantee a fairness in the process of channel allocation. The perfomrance of proposed protocols are evaluated in terms of throughput and delay with variations in offered load. Simulation results show that the proposed protocols have superior performance to conventional protocols.

• Journal of Power System Engineering
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• v.20 no.5
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• pp.52-59
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• 2016

Environmental Qualification has been almost developed except those of Non-Material Sub-components for valves and pumps though the time has only passed about 10years since EQ test launch of Korea. However EQ test has been performed by a few of engineers under the conditions that experience of EQ test is insufficient and EQ system is not developed completely. In recent years, Strengthen Nuclear Safety Regulation is being done Strictly Nuclear safety components Verification Procedure for Non-Material Sub-components, but the reports contain only performance test results, not Enviro nmental test methods relating to real Aging Degradation. In this Study, there were developed to performance systematically research to acquire EQ technology for five specimens of the Non-Material Sub-components in the Nuclear Power Plant.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.529-532
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• 2008

Recently the compound material has interested in using the structural material as the bridge member assembly. It is the lighter material against existing construction material and has excellent durability and economy. The existing floor of bridge has its short period to repair and replace compared to other parts of the bridge with the pavement and the shoe. These deteriorations of usage and safety by aging and corrosion are needed frequent maintenance. The use of compound material as a structural member suggests solve these problems. So this thesis evaluates the static and the fatigue performance for whether there are fiber lamination direction and stress concentration section of FRP floor plate, the compound material.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.122-123
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• 2019

Recently, road cutting works are frequently performed to repair aging underground utilities. However, the conventional road pavement cutting equipment in Korea generates a lot of noise and dust, and the development of high performance and eco-friendly equipment is required. This study classifies road cutting work and analyzes its work characteristics before improving road cutting machine. The classification and analysis results of this study will be used for the future productivity analysis and evaluation of road cutter developed.

• Journal of Applied Reliability
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• v.16 no.3
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• pp.208-215
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• 2016

Purpose: ASRP for the domestic development guided missiles requires not only for the reliability evaluation of the products in storage but also for the life cycle management of the products including development prototypes and initial production items. Methods: For this purpose, it should be performed to build a performance database before and after the accelerated aging test with shelf life items including development prototypes and initial production items, based on which the lifetime prediction should also be carried out. In addition, HILS must be applied for the acceptance test with the initial and follow-up production items, and also for ASRP for the long-term storage products in order to secure systematic quality assurance. Results: The results for the life cycle reliability Improving of domestic development of guided missiles are DB building of prescription Item performance, active application of HILS, Management associated with guided missiles life cycle and to Secure technology data about the introduction of foreign guided missiles. Conclusion: Furthermore, it is demanded that DTaQ, the managing agency of ASRP, actively take part in the process to maintain reliability engagement consistency over the life cycle of guided missiles.