• Journal of Practical Agriculture & Fisheries Research
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• v.3 no.1
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• pp.142-157
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• 2001

This study was conducted to get the basic information for promoting farm machinery productivity by surveying the regular maintenance and repair status of major farm machinery such as power tiller, farm tractor, rice transplanter and combine harvester. The survey was carried out through 9 provinces including Cheju province by direct visiting farmers with prepared questionnaire. The results of this study can be summarized as follows : 1. The average farming carrier of the surveyed farmers was 25.3 years, and 21-30 years of farming carrier showed the highest portion as 40.7%. The average carrier of using farm machinery was 9.4 years, and that was 14.9 years for power tiller, 8.3 years for farm tractor, 9.0 years for rice transplanter, 7.9 years for combine harvester, 7.5 years for mini tiller, 9.7 years for power sprayer, and 8.2 years for binder etc. 2. The regular maintenance for farm machinery was conducted mainly at repair shop (49.5%) or dealer agency (12.0%) as 61.5%, and 34.9% of farmers conducted the regular maintenance by themselves at their house. 3. The reasons for not-fully recognizing operation manual and insufficient before-, during-, after-maintenance of farm machinery were insufficient time for them (45.8%), troublesome (22.9%), unknown maintenance method (16.3%), unknown the necessity for maintenance (12.4%), and others (2.6%) in order. 4. For the annual exchange of engine oil, 3.2 times is necessary but actually 1.7 times was exchanged for power tiller, 4.3 times is necessary but actually 1.9 times was exchanged for farm tractor, 2.7 times is necessary but actually 1.7 times was exchanged for rice transplanter, 2.2 times is necessary but actually 2.3 times was exchanged combine harvester. 5. For the annual cleanness or exchange of fuel filter, 3.2 times is necessary but actually 1.1 times was done for power tiller, 4.3 times is necessary but actually 1.6 times was done for farm tractor, 2.7 times is necessary but actually 1.7 times was done for rice transplanter, 1.9 times is necessary but actually 0.8 times was done for combine harvester. 6. For the annual cleanness or exchange of air filter, 3.2 times is necessary but actually 1.4 times was done for power tiller, 4.2 times is necessary but actually 2.4 times was done for farm tractor, 2.6 times is necessary but actually 1.6 times was done for rice transplanter, 3.9 times is necessary but actually 7.0 times was done for combine harvester. 7. For the experience of breakdown related to maintenance, 5.3% of farmers experienced breakdown due to the insufficient exchange of engine oil, 7.7% of farmers experienced breakdown due to the insufficient cleanness or exchange of fuel filter, and 2.9% of farmers experienced breakdown due to the insufficient cleanness or exchange of air filter. 8. Most farmers (76.1%) recognized the necessity for agricultural machinery training or education, and most farmers preferred about one week for the training period, simple or ease maintenance for the training level, agricultural technical center or agricultural machinery manufacturer for the training agency. 9. Complete recognition of operation manual and sufficient before-, during-, and after-maintenance for farm machinery can minimize the breakdown as well as conduct suitable period farming, enlarge the endurance, prevent the safety accidents, and promote productivity of farm machinery. Therefore, these can be accomplished by the thorough training or education for agricultural machinery.

• Proceedings of the CALSEC Conference
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• 2004.02a
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• pp.345-349
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• 2004

·Emerging requirements for EC environments ： -At eun-time： Dynamic process composition with various networked resources, i.e., application or participants -At build ＆ maintenance time： Agile technical enhancements. e.g., evolution in standards · Open issues of WfMS(Bussler, 1999： Sayal et al., 2002)： -Heterogeneity ＆ interoperability -Adaptability and flexibility(omitted)

• Journal of the Korean Society for Precision Engineering
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• v.15 no.1
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• pp.19-25
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• 1998

Remote fault diagnosis and maintenance system using general telecommunication network is necessary for an effective fault diagnosis and higher productivity of NC machine tools. In order to monitor machine tool condition and diagnose alarm states due to electrical and mechanical faults, a remote data communication system for monitoring of NC machine fault diagnosis and status is developed. The developed system consists of (1) remote communication module among NC's and host PC using PSTN. (2) 8 channels analog data sensing module, (3) digital I/O module for control or NC machine, (4) communication module between NC machine and remote data communication system via RS-232C, and (5) software man-machine interface. Diagnostic monitoring results generated through a successive type inference engine are displayed in user-friendly graphics. The validity and reliability of the developed system is verified to be a powerful commercial version on a vertical machining center through a series of experiments.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.5
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• pp.556-565
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• 2016

As a result of the enforced control of emission, many devices, including the diesel particulate filter, have been installed in diesel cars to reduce the emission of particulate matters. In this study, a car fire case has been investigated and analyzed. A car fire broke out after the vehicle traveled a distance of 1.4 km from a car service center. The car was provided with DPF cleaning when the DPF warning light came on. After being dismantled in the engine room, the car's engine and gearbox were investigated. The findings showed that the rear part of the DPF metal case was melted and punctured, while the honeycomb filter of the DPF was damaged. The car fire was caused by an overheated DPF associated with inaccurate maintenance practice. Therefore, the responsibility of the fire rested on the car service center that performed the DPF cleaning.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.10
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• pp.1-8
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• 2021

Cylinder liners used in diesel engines of combat equipment are prone to cavitation due to wet cooling. The damage caused by erosion and corrosion due to cavitation has a fatal effect on the performance and lifespan of a diesel engine. Therefore, a study was conducted to improve the durability of cylinder liners. Two surface treatment techniques were proposed: nitriding and chrome plating. It was observed that the amount of erosion on the surface of nitride-treated cylinder liners was high because the surface-treated part eroded due to its weak impact resistance against the bubble explosion generated by cavitation. In contrast, the chrome-plated cylinder liner had a lower amount of erosion among the specimens subjected to the accelerated test. These results verified that the resistance of chrome-plated liners against cavitation is high. Therefore, it can withstand the impact of bubble explosion. If the chrome plating thickness is set with reference to the KS standard, an exceptional durability of abrasion, wear resistance, and corrosion resistance can be obtained. If the thickness is set between 120~250㎛, it is expected that the durability of the cylinder liner can be improved. Although a recovery method for corroded cylinder liners is suggested, the proposed method has an inherent risk of crack generation. Therefore, further research is required to solve this problem.

• Journal of Aerospace System Engineering
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• v.7 no.1
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• pp.8-18
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• 2013

Recently, the advanced condition monitoring methods such as the model-based method and the artificial intelligent method have been applied to maximize the availability as well as to minimize the maintenance cost of the aircraft gas turbines. Among them the non-linear GPA(Gas Path Analysis) method and the GA(Genetic Algorithms) have lots of advantages to diagnose the engines compared to other advanced condition monitoring methods such as the linear GPA, fuzzy logic and neural networks. Therefore this work applies both the non-linear GPA and the GA to diagnose AE3007 turbofan engine for an aircraft, and in case of having sensor noise and bias it is confirmed that the GA is better than the GPA through the comparison of two methods.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.4
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• pp.117-124
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• 2018

USA and Europe are leading the transport airplane industry. In Asia-Pacific region, air transportation and MRO industries are forecasted to be grown up rapidly. Furthermore, Japan and China entered into design and manufacture state of regional airplane, while developing countries entered into severe struggle competition for MRO industry. Global aircraft MRO and engine MRO industries are forecasted 3.4% and 7% annual growth respectively in the next decade. In this paper, authors propose promotion strategy for technology intensive MRO of aircraft engine to create a higher value-added business.

• Journal of Aerospace System Engineering
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• v.11 no.4
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• pp.22-29
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• 2017

A study is performed for the effective detection method of a fault which is occurred during operation in a small turbojet engine with non-linear characteristics used by unmanned air vehicle. For this study the non-linear dynamic model of the engine is derived from transient thermodynamic cycle analysis. Also for inducing real operation conditions the controller is developed associated with unscented Kalman filter to estimate noises. Sequential probability ratio test is introduced as a real time method to detect a fault which is manipulated for simulation as a malfunction of rotational speed sensor contaminated by large amount of noise. The method applied to the fault detection during operation verifies its effectiveness and high feasibility by showing good and definite decision performances of the fault.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.10
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• pp.717-727
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• 2022

An algorithm is realized for estimating the component fault and health diagnosis such as a deterioration. Based on the turbofan engine health diagnosis model, from the health parameters which are estimated by a real time tracking filter, the outliers are eliminated efficiently by an effective median filter to minimize an false alarm. The difference between the fault and deterioration trends is identified by the detection measure for abrupt change, thereby the clear diagnosis classifying the fault and the health condition is possible. The effectiveness of the algorithm for fault and health diagnosis is verified from the simulated results of engine component faults and deterioration.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.5
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• pp.108-120
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• 2017

The technology for health management of gas turbine engine has grown with engine development itself for 60 years and regarded as important area for performance monitoring and maintenance of the system. This technology which is based on several areas such as advanced measurement technology, electronics, software technology and reliable system modeling is realized. This paper analyzed the past, current and future technical trend of a technically advanced country and compared with domestic research status. Based on the analysis, the key research topics for the realization of technology is suggested.