• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.43 no.6
• /
• pp.689-693
• /
• 2023

Domestic bridges with a service life of more than 30 years are expected to account for approximately 54% of all bridges within the next 10 years. As bridges rapidly deteriorate, it is necessary to establish an appropriate maintenance plan. Recent domestic and international research have focused on the integration of BIM to digitize bridge maintenance information and then enhance accessibility and usability of the information. Accordingly, this study developed a BIM-FEM interoperability algorithm for bridge decks to convert maintenance information into data and efficiently manage the history of maintenance. After creating an initial crack BIM based on an exterior damage map, bridge specification and damage information were linked to a numerical analysis that performs damage analysis considering damage scenarios and design loads. The spread of cracks obtained from the analysis results were updated into the BIM. Based on the damage spread information on the BIM, an automated technology was also developed to assess both the current and future condition ratings of the bridge deck. This approach can enable an efficient maintenance of the deck using the history data from bridge inspection and diagnosis as well as future information on cracks and defects. The expected early detection and prevention would ultimately improve the lifespan and safety of bridges.

• Progress in Superconductivity and Cryogenics
• /
• v.15 no.4
• /
• pp.6-9
• /
• 2013

Korea Superconducting Tokamak Advanced Research (KSTAR) has a helium refrigeration system (HRS) with the cooling capacity of 9 kW at 4.5 K. Main cold components are composed of 300 tons of superconducting (SC) magnets, main cryostat thermal shields, and SC current feeder system. The HRS comprises six gas storage tanks, a liquid nitrogen tank, the room temperature compression sector, the cold box (C/B), the 1st stage helium distribution box (DB#1), the PLC base local control system interconnected to central control tower and so on. Between HRS and cold components, there's another distribution box (DB#2) nearby the KSTAR device. The entire KSTAR device was constructed in 2007 and has been operated since 2008. This paper will present the maintenance result of the KSTAR HRS during the campaign and discuss the operation record and maintenance history of the KSTAR HRS.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.11
• /
• pp.130-137
• /
• 2017

To maintain traffic safety during the target lifetime of bridges, it is essential to secure an appropriate maintenance budget and allocate that budget appropriately. This paper proposes a reasonable budget allocation system that considers various impact factors to improve the conventional budget allocation method simply considering the bridge scale. The maintenance action rate model and the unit cost model based on the prior maintenance history were developed to allocate appropriately the bridge maintenance budget for the total bridges of the management organization with the target management level. A method to determine the optimal budget allocation ratio for each management subject was proposed and case analysis was conducted using the proposed model. Proper budget allocation was made considering the bridge types, current safety level, and service life as well as the bridge size as an impact factor of the budget allocation of the bridge. The developed method can prevent budget waste and provide a rational basis for budget allocation by implementing the rational budget distribution.

• Journal of Korean Medicine for Obesity Research
• /
• v.19 no.2
• /
• pp.119-136
• /
• 2019

Objectives: People often fail to maintain their weight even though they have succeeded in weight loss. The purpose of this study was to review previously published study results with regards to the predictive factors associated with weight loss maintenance after successful weight loss. Methods: The authors searched for the articles related to weight loss maintenance after successful weight loss, published up until June 2019 on PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), Embase, Research Information Sharing Service (RISS), and Koreanstudies Information Service System (KISS). A total of 76 articles were finally selected. From the study results, changeable and unchangeable predictors were extracted, and these predictors were examined according to detailed categories. Results: The changeable predictors of weight loss maintenance included behavioral factors, psychological factors and treatment process-related factors, whereas the unchangeable predictors included genetic and physiological factors, demographic factors, history of treatment on obesity-related factors. The main factors of weight loss maintenance were changeable predictors such as healthy eating habits, dietary intake control, binge eating control, regular exercise and physical activity, depression and stress control, social supports, self-regulation, self-weighing and initial weight loss and unchangeable predictors such as low initial weight and maximum lifetime weight. Conclusions: The results of our review results suggest that changeable and unchangeable predictors of weight loss maintenance should be carefully examined during treatments of obesity.

• Journal of Korean Society of Disaster and Security
• /
• v.9 no.1
• /
• pp.33-38
• /
• 2016

Real time location system was development for safety management at road and bridge maintenance field. The system can check the real-time location detection, movement history, behavior of a number of laborers. The system consisted of a Bluetooth and ZigBee that uses low-power. It had a very large error that the previous method for the position recognition by triangulation using the RSSI. Because This study proposed a new distance measurement and correction scheme using RSSI and accelerometer. It was evaluated in the maintenance field. A development system were evaluated in the field, the results are shown an error between 0.2 m and 0.4 m. And through the acceleration of history it was confirmed by determining possible to determine the safety situation of the laborers.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.7 no.5
• /
• pp.1153-1164
• /
• 2012

In this paper, we propose an efficient car management system based on object-oriented modeling using car number recognition and smart phone. The proposed system perceives car number of repair vehicle after recognizing the licence plate using an IP camera in real time. And then, existing repair history information of the recognized car is be displayed in DID. In addition, maintenance process is shooting video while auto maintenance mechanic repairs car through IP-camera. That will be provide customer car identification and repairs history management function by sending key frames extracted from recorded video automatically. We provide user graphic interface based on web and mobile for your convenience. The module design of the proposed system apply software design modeling based on granular object-oriented considering reuse and extensibility after implementation. Car repairs center and maintenance companies can improve business efficiency, as well as the requested vehicle repair can increase customer confidence.

• Journal of architectural history
• /
• v.20 no.1
• /
• pp.23-39
• /
• 2011

The Sungnyemun roofing tiles were twice disassembled for maintenance work, in 1963 and 1997, and modern tiles were applied in 1997. However, besides differing in visual appearance, the modern tiles had distinctly different physical properties. A study has been carried out on 22 different tiles, including original Sungnyemun tiles, modern tiles applied during maintenance, traditional tiles made by tile-makers, and others, to examine their physical properties, such as bending strength, frost resistance, absorption, whole-rock magnetic susceptibility, chromaticity, differential thermal analysis, and other characteristics. Since the method of making modern tiles involves compressing clay in a vacuum, modern tiles showed relatively greater bending strength and specific gravity, while Sungnyemun tiles and those made by tile-makers, in comparison, demonstrated less bending strength and specific gravity owing to their production method of 'treading,' in which clay is mixed by having someone tread upon it repeatedly. Over time, the absorption rate of the original tile used for Sungyemun gradually decreased from 21% to 14.7%; traditional tiles from tile-makers showed absorption rates of 17%, while the absorption rate of modern tiles was just 1%, which is significantly low. As for frost resistance, Sungnyemun tiles and traditional tiles from tile-makers showed cracking and exfoliation after being subjected to testing 4 or 5 times, while slight cracking was seen on the surface for modern tiles after 1ngy, or 3 times. In other words, no significant difference from influence by frost was found. According to the results of differential thermal analysis, the plastic temperature was shown to have been no less than 1, $on^{\circ}C$ for all types of tile, and cristobalite was measuredthrough XRD analysis from a Sungnyemun female tile applied during maintenance in 1963, which appeared to have been plasticized at between $1,200^{\circ}C{\sim}1,300^{\circ}C$. Based on these research results on the physical properties of tiles from the Sungnyemun roof, a fundamental production method for tiles to be applied in the restoration of Sungnyemun has been identified.

• The Journal of the Convergence on Culture Technology
• /
• v.8 no.3
• /
• pp.239-244
• /
• 2022

In this study, the key parameters affecting the deterioration of each track type were derived based on field inspections and laboratory tests. The existing track deterioration model was limited to the ballasted tracks, and the deterioration evaluation of concrete tracks was insufficient. In this study, the laboratory test was performed to evaluate the performance and condition of track components to derive the deterioration factors reflecting the characteristics of various track structures. In addition, through analysis of track maintenance history data, parameters affecting track deterioration and maintenance were derived. The key parameters for presenting a track deterioration model based on the track performance of ballasted and concrete tracks through field inspection, track maintenance history data analysis, and performance test of track components using on-site specimens were identified as track support stiffness, Ballast gravel, track settlement and Resilience pad were presented.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.11 no.3
• /
• pp.185-191
• /
• 2007

For the seismic performance enhancement of residential flat plate structure and for the selection of earthquake records, the possibility of base isolation is evaluated and the time history results are reviewed. By evaluating a base isolated stiffness, a target period, and an envelope curve analysis, seismic performance of structure, which has strong rotational mode, is evaluated. For the propriety evaluation of earthquake records usage and scaling method, time history analysis is done with variables such as DBE(design base earthquake) level, MCE(maximum considerable earthquake) level, and 1.4DBE level. From the analysis results, following conclusions can be made; the earthquake records, which are used in base isolation analysis, should be selected by similar soil type which the structure is considered, and should be intensity scaled in a range of mean ${\pm}$ standard deviation of code based design response spectrum.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.12
• /
• pp.60-68
• /
• 2019

For effective building maintenance, the collection and management of various maintenance date such as work history information and material information is required. Despite the introduction of information management technologies and systems to reduce the amount of maintenance work of buildings, which have become larger and more complex, the maintenance information is not being utilized properly. As an alternative, research on the introduction and utilization of BIM is being conducted continuously. However, the BIM models generated at the design phase are not utilized in practice due to a lack of architectural maintenance information. This study proposed a COBie document prototype to support BIM-based smart maintenance tasks performed by building managers. In order to formalize various types of maintenance work procedures, a BIM-based maintenance process model is presented in two categories: inspection and maintenance. Among the BIM attribute data of the BIM model generated at the design phase, the parameters corresponding to the maintenance necessary information for each basic process are derived. Based on this, we proposed a COBie document prototype consisting of seven spreadsheets. The results of a case study confirmed that the KBIMS library-based BIM model created at the design phase without the maintenance information can be used at the maintenance phase.