• Proceedings of the KSR Conference
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• 2003.10b
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• pp.454-459
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• 2003

The process of determining whether, when, where and how to intervene, of deciding on optimum allocation of resources and minimizing the cost is a very complex problem: different track sections tend to behave differently under the effects of loading; decision-making processes for maintenance work are closely interrelated technically and economically; decision-making for maintenance plans is based on a large quantity of technical and economic information, extensive knowledge and above all experience. For that reason, It is considered very important to develope objective and computer-aided decision-making support system for track maintenance plan. On this paper, we reviewed ECOTRACK system and present the plan of develope decision-making support system for track maintenance appropriate to local condition.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.120-121
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• 2013

Apartment houses maintenance like remodeling in at issue and the importance is getting higher. On this study, we analyzed a variety of the influence factor affected building's maintenance expenses. circumstance influence factor about maintenance expenses is classified into region(big city, small and medium city), (area of high snowfall), (downpour region), (earthquake region), location(waterfront, inland province), using condition(mixed use, single use), frequency of use(kindergarten, middle school, high school), architecture method(reconstruction, construction).

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1185-1194
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• 2022

The maintenance of condenser main pipe is the key to achieve film-forming amine maintenance effectiveness. In this work, oxygen content, pH and temperature of the solution were controlled to simulate the condition of condenser main pipe, and magnetite coated carbon steel sample was prepared by pre-oxidization. CAM was used to characterize the hydrophobicity of film formed samples. Hydrophobic film was formed on pre-oxidized carbon steel samples when octadecylamine concentration reaches 20 mg/kg. SEM, EDS, EIS, and PD were used to characterize the influence of octadecylamine concentration on maintenance effectiveness. It was found that the maintenance effectiveness was enhanced and the corrosion rate was suppressed with the increase of octadecylamine concentration. FIB and TEM were used to detect the adsorbed octadecylamine film thickness founding that octadecylamine adsorbed onto the surface of pre-oxidized carbon steel by multi-layer adsorption mechanism.

• Journal of the Korea Institute of Building Construction
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• v.7 no.1 s.23
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• pp.99-106
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• 2007

Water leakage could be caused deterioration of environmental conditions, user condition, reduction of life span and long term safety in underground concrete structure. Many materials and construction method to repair on these problems have been developed, however, it is not proper to successful repair or raise problem of increasing repair cost However, there are many limitations as practical appraisal methods due to different view of reliability for test methods. Because, it was not enough that the technical objectivity could be lack and also application of environmental condition is inadequate. In this paper, we suggest varied test methods divided to appraisal for property of matter, construction, manufacturing, specification and maintenance, friendly environmental condition. It could be more practical as a objective standard considering various angles. In summery, it should be subdivided and differentiated to accomplish proper application and to select proper materials and construction method for repair even if the synthetical condition is very complicated.

• Journal of the Korean Society of Food Culture
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• v.10 no.1
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• pp.1-10
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• 1995

The purpose of this study is to identify potentially hazardous factors which can contribute to the outbreak of food borne disease and present more practical management methods in terms of sanitary management of cooking equipment and personal hygiene. 230 Korean-style restaurants in Seoul were surveyed in the same manner on the published study-A study for the Improvement of Sanitary Condition in Korean style-restaurant in Seoul city area (I). Sanitary check-lists were developed to evaluate the sanitary status of cooking equipment and personal hygiene of employee. The sanitary condition of cooking equipment the maintenance of refrigeration, food habits and personal hygiene were assessed by the sanitary score. The sanitary condition of cooking equipment, the maintenance of refrigeration as well as food habits and personal hygiene employee was in good condition. The effective sanitation education and training for good service workers should be practice for the improvement of sanitary management of cooking equipment and personal hygiene.

• International Journal of Highway Engineering
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• v.19 no.5
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• pp.1-11
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• 2017

PURPOSES : This study is aimed at development of a stochastic pavement deterioration forecasting model using National Highway Pavement Condition Index (NHPCI) to support infrastructure asset management. Using this model, the deterioration process regarding life expectancy, deterioration speed change, and reliability were estimated. METHODS : Eight years of Long-Term Pavement Performance (LTPP) data fused with traffic loads (Equivalent Single Axle Loads; ESAL) and structural capacity (Structural Number of Pavement; SNP) were used for the deterioration modeling. As an ideal stochastic model for asset management, Bayesian Markov multi-state exponential hazard model was introduced. RESULTS:The interval of NHPCI was empirically distributed from 8 to 2, and the estimation functions of individual condition indices (crack, rutting, and IRI) in conjunction with the NHPCI index were suggested. The derived deterioration curve shows that life expectancies for the preventive maintenance level was 8.34 years. The general life expectancy was 12.77 years and located in the statistical interval of 11.10-15.58 years at a 95.5% reliability level. CONCLUSIONS : This study originates and contributes to suggesting a simple way to develop a pavement deterioration model using the total condition index that considers road user satisfaction. A definition for level of service system and the corresponding life expectancies are useful for building long-term maintenance plan, especially in Life Cycle Cost Analysis (LCCA) work.

• Journal of the Korean Institute of Educational Facilities
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• v.24 no.5
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• pp.11-18
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• 2017

An university dorm has significant implications in terms of providing residential, living, and learning spaces. With its supportive function, a dorm enables each university to provide higher level of education. The operation & maintenance(O&M) condition of the dorm has a decisive effect on the students' satisfaction. Accordingly, high levels of O&M services should be performed for students. However, Korean dorms are being operated and maintained by their own O&M guidelines without the consideration of spatial characteristics of dorm facilities and the comprehensive and systematic understanding on effective O&M processes. Given the fact that dorm facility can be a crucial factor in determining the entire quality of university and its O&M condition is closely related to the satisfaction of students, it is imperative that we need to pay more attention to the O&M condition and services. Therefore, the main objective of this research is to improve dorm students' satisfaction levels by applying different O&M method, preventive maintenance rather than reactive maintenance which has been performed so far. In ordering for doing it, 'Facility Management(FM) Standard' from KS, 'Facility Performance Indicator(FPI)' from APPA: Leadership in educational facilities and 'Building O&M Inspection Manual' from Korean Ministry of Land, Infrastructure and Transport were analyzed to come up with 15 significant O&M factors. After extracting O&M factors, the survey was conducted to determine importance rate and performance rate of each O&M factor. Using the Important-Performance Analysis(IPA), the priority of 15 O&M factors was established. The result of this research will be helpful for the efficient dorm facility O&M services and for facility managers to appropriately allocate the limited resources and human power.

• Structural Monitoring and Maintenance
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• v.2 no.3
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• pp.283-300
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• 2015

Visual condition inspections remain paramount to assessing the current deterioration status of a bridge and assigning remediation or maintenance tasks so as to ensure the ongoing serviceability of the structure. However, in recent years, there has been an increasing backlog of maintenance activities. Existing research reveals that this is attributable to the labour-intensive, subjective and disruptive nature of the current bridge inspection method. Current processes ultimately require lane closures, traffic guidance schemes and inspection equipment. This not only increases the whole-of-life costs of the bridge, but also increases the risk to the travelling public as issues affecting the structural integrity may go unaddressed. As a tool for bridge condition inspections, Unmanned Aerial Vehicles (UAVs) or, drones, offer considerable potential, allowing a bridge to be visually assessed without the need for inspectors to walk across the deck or utilise under-bridge inspection units. With current inspection processes placing additional strain on the existing bridge maintenance resources, the technology has the potential to significantly reduce the overall inspection costs and disruption caused to the travelling public. In addition to this, the use of automated aerial image capture enables engineers to better understand a situation through the 3D spatial context offered by UAV systems. However, the use of UAV for bridge inspection involves a number of critical issues to be resolved, including stability and accuracy of control, and safety to people. SLAM (Simultaneous Localisation and Mapping) is a technique that could be used by a UAV to build a map of the bridge underneath, while simultaneously determining its location on the constructed map. While there are considerable economic and risk-related benefits created through introducing entirely new ways of inspecting bridges and visualising information, there also remain hindrances to the wider deployment of UAVs. This study is to provide a context for use of UAVs for conducting visual bridge inspections, in addition to addressing the obstacles that are required to be overcome in order for the technology to be integrated into current practice.

• Journal of the Society of Naval Architects of Korea
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• v.59 no.4
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• pp.200-206
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• 2022

This study is to develop database by an experimental method for the development of condition based maintenance for auxiliary equipment in marine engine systems. Existing ships have been performing regular maintenance, so the actual measurement data development is very incomplete. Therefore, it is best to develop a database on land tests. In this paper, a database developed by an experimental method is presented. First, failure case analysis and reliability analysis were performed to select a failure mode. For the failure simulation test, a test bed for land testing was developed. The failure simulation test was performed based on the failure simulation scenario in which the failure simulation test plan was defined. A 1.5TB failure simulation database has been developed, and it is expected to serve as a basis for ship failure diagnosis and prediction algorithm model development.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.2
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• pp.95-109
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• 2023

In the 4th industrial revolution, changes in the technological paradigm have had a direct impact on the maintenance system of ships. The 2-stroke low speed engine system integrates with the core equipment required for propulsive power. The Condition Based Management (CBM) is defined as a technology that predictive maintenance methods in existing calender-based or running time based maintenance systems by monitoring the condition of machinery and diagnosis/prognosis failures. In this study, we have established a framework for CBM technology development on our own, and are engaged in engineering-based failure analysis, data development and management, data feature analysis and pre-processing, and verified the reliability of failure mode DB using LSTM algorithms. We developed various simulated failure mode scenarios for 2-stroke low speed engine and researched to produce data on onshore basis test_beds. The analysis and pre-processing of normal and abnormal status data acquired through failure mode simulation experiment used various Exploratory Data Analysis (EDA) techniques to feature extract not only data on the performance and efficiency of 2-stroke low speed engine but also key feature data using multivariate statistical analysis. In addition, by developing an LSTM classification algorithm, we tried to verify the reliability of various failure mode data with time-series characteristics.