• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.3
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• pp.191-201
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• 2001

In spite of the increasing construction of segmental PSC box girder bridges, the techniques associated with real-time monitoring, construction control and safety assessment during construction have been less developed compared with the construction techniques. Thus, the development of an integrated system including real-time measurement and monitoring, control and safety assessment system during construction is necessary fur more safe and precise construction of the bridges. This study presents a prototype integrated monitoring system for preventing abnormal behavior and accidents under construction stages, that consist of behavior control system for precise construction, reliability-based safety assessment system, and structural analysis. Also, a prototype software system is developed on the basis of the proposed model. It is successfully applied to the Sea-Hae Grand Bridge built by FCM. The integrated system model and software system can be utilized for the safe and precise construction of segmental PSC bridges during construction.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.16 no.2
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• pp.1-12
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• 2013

This study reviews the current conditions of the completed 'Ecosystem Conservation Fund Return Project' sites to suggest management methods for their conservation and sustainability. For the scope of the study, five microsites of completed return projects in Seoul were selected and their project planning documents were reviewed to help with site surveying and analysis. To increase the accuracy of the site surveying and analysis, and to evaluate the management problems from different perspectives, the site managers were interviewed in-depth. The experts were surveyed as well to develop a realistic and practical improvement method. The survey results helped to categorize the post-management problems, and separate improvement methods were suggested for each category. First, the post-management guidelines are proposed for the ecosystem-based environment/ecosystem environment, user management, and monitoring. These guidelines will increase the expertise and practicality of the management principles. Second, the regulations for the participation of expert management enterprises and the development of separate monitoring or maintenance management team are suggested. These regulations will improve the participation of experts and consistency of management systems. Third, the post monitoring or maintenance management during the year after the project completion should be set as a separate project to secure budget. Furthermore, policies and/or institutions should be established to set a portion of ecosystem conservation return fund or a grant for post monitoring and maintenance management. Forth, as a way of adaptive management, at least more than three years of post-management should be evaluated under detailed categories and vigorous standard to improve the institutional operation for 'Ecosystem Conservation Fund Return Projects'.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.4
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• pp.161-167
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• 2020

In the process of cutting large aircraft parts, the tool may be abnormally worn or damaged due to various factors such as mechanical vibration, disturbances such as chips, and physical properties of the workpiece, which may result in deterioration of the surface quality of the workpiece. Because workpieces used for large aircrafts parts are expensive and require strict processing quality, a maintenance plan is required to minimize the deterioration of the workpiece quality that can be caused by unexpected abnormalities of the tool and take maintenance measures at an earlier stage that does not adversely affect the machining. In this paper, we propose a method to indirectly monitor the tool condition that can affect the machining quality of large aircraft parts through real-time monitoring of the current signal applied to the spindle motor during machining by comparing whether the monitored current shows an abnormal pattern during actual machining by using this as a reference pattern. First, 30 types of tools are used for machining large aircraft parts, and three tools with relatively frequent breakages among these tools were selected as monitoring targets by reflecting the opinions of processing experts in the field. Second, when creating the CNC machining program, the M code, which is a CNC auxiliary function, is inserted at the starting and ending positions of the tool to be monitored using the editing tool, so that monitoring start and end times can be notified. Third, the monitoring program was run with the M code signal notified from the CNC controller by using the DAQ (Data Acquisition) device, and the machine learning algorithms for detecting abnormality of the current signal received in real time could be used to determine whether there was an abnormality. Fourth, through the implementation of the prototype system, the feasibility of the method proposed in this paper was shown and verified through an actual example.

• Journal of Korea Multimedia Society
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• v.19 no.2
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• pp.405-410
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• 2016

Elevator industry is a field that is mechanical, electrical and electronic technology and constantly requires inspection and maintenance considering various applications and various types. Recently, various elevator control and monitoring technologies with IT are developing for elevators on land. But technologies with IT have been hardly done in marine elevator that is consistently assured safety and reliability of life cycle for its parts in poor environment. In this paper, we implemented embedded main controller, floor controller and car controller that meet the requirements and use NMEA network protocol by analyzing home and abroad integrated elevator operation and management systems. Especially, we secured reliability of maintenance by real-time fault diagnosis and control that was implemented with limit switch, gyro sensor, temperature/humidity/barometric pressure sensor and fire detection sensor thinking over the environmental conditions of terrestrial and marine elevator.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1245-1247
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• 2001

This paper discusses that the maintenance of the propulsion equipment in railway rolling stock. Condition monitoring of railway equipment is the need for integration of remote condition monitoring with maintenance management strategies. The paper outlines research leading to the design and development of a prototype control and monitoring system for propulsion equipment.

• Tribology and Lubricants
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• v.10 no.4
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• pp.51-58
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• 1994

Condition monitoring technology has recently been received much attention in the light of its significance on the maintenance of complex machineries such as turbines in power plants. Currently, turbines in power plants are maintained by scheduled overhaul based on the manufacturer's recommendations and the utility's experience. Although this preventive maintenance is known to be very effective, operators have less access to identify failure of elements when it happens between overhaul period. Therefore, in this study, a development of a on-line condition monitoring system through wear debris analysis of lubricating oils is aimed with a view to detecting abnormal wear behaviour of bearings and other wet-components at an early stage, allowing better outage scheduling and minimizing forced outages. For field application purposes, the on-line system developed was installed on the turbine of the No.4 unit at Ulsan Power Plant and its performance has been evaluated on site.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.291-295
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• 2009

We did the blooth module test as a pre-test of wireless sensor monitoring system, which for the improving of on-condition maintenance reliability, on the train. In this test, we examined the communication environment of wireless sensor monitoring system by the acceleration date and frequency date in the real train structure during the operation. Also based on this results, we did the experimental verification of the sensor power system which use piezoelectric energy conversion technology by the theoretical modeling for the applying on the train on-condition maintenance.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.1
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• pp.33-40
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• 2014

Air compressor is an important facility with electric power in the industry. However, because of the noise and vibration of air compressor and is installed outside the building management difficulty. In this study, MCP (Micro Control Processor) to remote monitoring of the air compressor via the compressed air through improved quality and allows stable maintenance were designed. So, increase the productivity improvement of energy-saving effect can be obtained. Remote real-time information stored on your PC to manage air compressor equipment was higher reliability. Monitoring system is developed in this study was applied to embedded systems. It is easy to install air compressor, and low maintenance costs was to raise the economic impact.

• Structural Monitoring and Maintenance
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• v.6 no.3
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• pp.237-254
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• 2019

This paper presents an improved time series based damage detection approach with experimental verifications for detection, localization, and quantification of damage in shear-type structures under varying mass effects using output-only vibration data. The proposed method can be very effective for automated monitoring of buildings to develop proactive maintenance strategies. In this method, Auto-Regressive Moving Average models with eXogenous inputs (ARMAX) are built to represent the dynamic relationship of different sensor clusters. The damage features are extracted based on the relative difference of the ARMAX model coefficients to identify the existence, location and severity of damage of stiffness and mass separately. The results from a laboratory-scale shear type structure show that different damage scenarios are revealed successfully using the approach. At the end of this paper, the methodology limitations are also discussed, especially when simultaneous occurrence of mass and stiffness damage at multiple locations.

• Structural Monitoring and Maintenance
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• v.3 no.3
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• pp.259-276
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• 2016

Historically the UK has been a pioneer and early adopter of experimental investigation techniques on new and operation structures, a technology that would now be descried as 'structural health monitoring' (SHM), yet few of these investigations have been enduring or carried out on the long span or tall structures that feature in flagship SHM applications in the Far East.