• Structural Monitoring and Maintenance
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• v.5 no.4
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• pp.445-461
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• 2018

The aim of this research is to evaluate the effects of the number of spans, height of spans, number of floors, height of floors, column to beam moment of inertia ratio, and plastic joints distance of beams from columns on the ductility of moment frames. For the facility in controlling the ductility of the frames, this paper offers a simple relation instead of complex equations of different codes. For this purpose, 500 analyzed and designed frames were randomly selected, and their ductility was calculated by the use of nonlinear static analysis. The results cleared that the column-to-beam moment of inertia ratio had the highest effect on ductility, and if this relation was more than 2.8, there would be no need for using the complex relations of codes for controlling the ductility of frames. Finally, the ductility of the most frames of this research could be estimated by using the combination of genetic algorithm and artificial neural networks properly.

• Journal of Ocean Engineering and Technology
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• v.33 no.5
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• pp.421-426
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• 2019

The directivity of an underwater sound source should be measured in an acoustically open field such as a calm sea or lake, or an anechoic water tank facility. However, technical difficulties arise when practically implementing this in open fields. Signal processing-based techniques such as a sound intensity method and near-field acoustic holography have been adopted to overcome the problem, but these are inefficient in terms of acquisition and maintenance costs. This study established a simple directivity estimation technique with data acquisition, filtering, and analysis tools. A numerical simulation based on an acoustic radiosity method showed that the technique is practicable for sound source directivity estimation in a diffused reverberant acoustic field like a reverberant water tank.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.5
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• pp.356-364
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• 2019

In this study, major problems, such as licensing problems due to civil complaints, deterioration of facility period, and damage of modules, are exposed to many problems in domestic businesses. Particularly, the photovoltaic (PV) modules applied to early PV systems have been repaired and replaced over the past two decades, and a new module-based aging detection method is needed to expand the maintenance market and stabilize and repair power supplies. PV modules in a PV system use a string that is configured in series to generate high voltage. However, even if only one module of the solar modules connected in series ages, the power generation efficiency of the aged string is reduced. Therefore, we propose a topology that can measure the instantaneous PV characteristic curve to determine the aging module in the solar string and the aging judgment algorithm using the measured PV characteristic curve.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.161.3-161
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• 2001

This paper describes design features of a cleaning robot for use in a radioactive zone of the Isolation room of the Irradiated Material Examination Facility (IMEF) at Korea Atomic Energy Research Institute (KAERI). This cleaning robot is intended to completely eliminate human interaction with hazardous radioactive contaminants. The clean ing robot that is operated either by manual mode or by autonomous mode is designed to be capable of cleaning the isolation room´s floor surface and collecting dry nuclear fuel debris and other radioactive waste placed on the floor. The functional, mechanical and electrical design considerations of the cleaning robot in terms of remote cleanup operation and remote maintenance at a radioactive environment are presented. A graphical representation of the cleaning ...

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1485-1490
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• 2009

This paper discusses cases of infrastructure asset management in the U.S., Canada, and Australia and investigates infrastructure management in Korea in order to set the direction for the asset management improvement. The definitions of infrastructure asset management from various entities are introduced and implementation framework and organizational structures are described. The investigation on Korean public asset management practices finds the strong and weak points and defines the requirements and considerations to further improve the current practices. This paper will assist adopting infrastructure asset management in Korea and provide guide for the infrastructure maintenance.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.803-804
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• 2009

To accommodate constantly growing knowledge in scientific discourse that is revised over time by domain experts, we need to also evolve our ontology. The body of knowledge will get structured and refined as we develop a deeper understanding of issues. Keeping trail of new changes in semantically rich and formally sound mechanism has pragmatic advantages for providing the undo and redo facility and ontology recovery to a previous state. In this research, we have proposed a framework that support change logging and then using these logged changes for reverting ontology to a previous consistent state and visualization of change effects on ontology. The system is compared with ChangesTab of $Prot{\acute{e}}g{\acute{e}}$ and the results depict better accuracy for our system.

• Korean Journal of Ecology and Environment
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• v.36 no.4 s.105
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• pp.467-472
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• 2003

In this study, an algal fence was developed and applied to reduce the input of algal scum into the water intake facility. The effectiveness of vertical algal fences(overlapped three types of meshes, (312 ${\mu}m$ ${\times}$ 375 ${\mu}m$, 390 ${\mu}m$ ${\times}$ 450 ${\mu}m$, and 0,7 cm ${\times}$ 1cm; vertical depth, 1.5 m; length of fence, about 120 m)) was experimentally tested at a water intake facility (Mulgum, lower Nakdong River). The application of the fence resulted in the statistically significant difference of algal biomass between inside and outside of the fence. According to ANOVA test, chi. a concentration in Day-1showed large difference at each depth of 0, 1, 2 m (0.001> p at each depth, n = 16 respectively). Especially large difference was observed at 0 and 1 m depth. However, the fence was only effective for a short period and its efficiency declined by Day-5after the installation. When better maintenance options for the fence are prepared, e.g. mechanical installation and periodic backwashing of the fence, the performance of algal fence may be sustained. In addition, reliable models for bloom prediction are required to provide an advanced indication of the optimal timing for the installation so that effective operation would be achieved.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.529-532
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• 2003

Efficiency and efficient management on maintenance/repair/operation (MRO) phase is getting important with advance in technologies and complex functionalities of building and facility. Using software systems as well as advanced hardware systems in MRO area is spreading along with this trend to take advantage of information technology. Information of building and facility for MRO phase is derived from engineering/procurement/construction (EPC) phase. But most current commercial software systems in EPC and MRO are focusing on their own phase, which arise lack of consistency of information from EPC to MRO phase. But, the information system now used at the MRO phase stop flowing the building and the facilities information and then newly create. Moreover, from all asset management point of view, asset particulars such as the structures and equipments are different the value fluctuation. In order to reflect these information rationally, the construction costs are correctly distributed and the initial price of the asset particulars have to be estimated. In this study, develop the information model which can apply the cost information at the EPC phase to the MRO phase.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.4893-4901
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• 2013

In order for a machine, especially used in the defense industry, to consistently operate during its life-time, lots of study has been done in machine design as well as machine maintenance. However, the realistic study is necessary in management and operation of a military support facility, where spare parts are stored and retrieved. In this paper, efficient arrangement of spare parts are proposed to acquire increased in efficiency and decreased in cost for operation management of the military support facility. First, spare parts is assorted by MTBF(Mean Time Between Failure) and divided in to three groups A/B/C as an alternative arrangement. Each defined alternatives will go under simulations and RULA(Rapid Upper Limb Assessment), which is posture classification scheme evaluation attributes, to find working time and posture difficulty and lastly by entropy measurement to be selected. This research proposes the efficient spare parts arrangement in military support facility to minimize working time and posture difficulty. By taking system and human engineering approach together into consideration, it will lead to show a specific value.

• Journal of the Society of Disaster Information
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• v.17 no.2
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• pp.254-265
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• 2021

Purpose: Inspection and diagnosis on the performance and safety through domestic port facilities have been conducted for over 20 years. However, the long-term development strategies and directions for facility renewal and performance improvement using the diagnosis history and results are not working in realistically. In particular, in the case of port structures with a long service life, there are many problems in terms of safety and functionality due to increasing of the large-sized ships, of port use frequency, and the effects of natural disasters due to climate change. Method: In this study, the maintenance history data of the gravity type quay in element level were collected, defined as big data, and a predictive approximation model was derived to estimate the pattern of deterioration and aging of the facility of project level based on the data. In particular, we compared and proposed models suitable for the use of big data by examining the validity of the state-based deterioration pattern and deterioration approximation model generated through machine learning algorithms of GP and SGP techniques. Result: As a result of reviewing the suitability of the proposed technique, it was considered that the RMSE and R² in GP technique were 0.9854 and 0.0721, and the SGP technique was 0.7246 and 0.2518. Conclusion: This research through machine learning techniques is expected to play an important role in decision-making on investment in port facilities in the future if port facility data collection is continuously performed in the future.