• Journal of the Korean Operations Research and Management Science Society
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• v.27 no.2
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• pp.33-49
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• 2002

CBM (Condition-Based Maintenance) has increasingly drawn attention in industry because of its many benefits. CBM Problem Is characterized as a state-dependent scheduling model that demands simultaneous maintenance actions, each for an attribute that influences on machine condition. This problem is very hard to solve within conventional Markov decision process framework. In this paper, we present an intelligent machine maintenance scheduler, for which a new incremental decision tree learning method as evolutionary system identification model and shortest path problem as schedule generation model are developed. Although our approach does not guarantee an optimal scheduling policy in mathematical viewpoint, we verified through simulation based experiment that the intelligent scheduler is capable of providing good scheduling policy that can be used in practice.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.323-324
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• 2006

This paper presents dynamics of register error on a compensator roll type converting machine. Though a register control is an important aspect of a converting machine, it has not been taken into account as a main subject. Lately, demands for high speed converting machines over 500mpm(m/min) are raising but domestic converting industries can not come up with the high speed machines because capacities fur designing of the converting machine is restricted lower than 300mpm. Moreover register control is the key to product flexible displays through roll-to-roll systems. In this paper, a compensator roll type register controller is analyzed using mathematical model of register error. A case study for reducing transient register errors is discussed.

• Journal of Korean Institute of Industrial Engineers
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• v.35 no.4
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• pp.218-225
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• 2009

This paper considers a parallel-machine scheduling problem with job release times and sequence-dependent setup times. The objective of this problem is to determine the allocation policy of jobs and the scheduling policy of machines so as to minimize the weighted sum of setup times, delay times, and tardy times. A mathematical model for optimal solution is derived and a meta heuristic algorithm based on the improved ant colony system is proposed in this paper. The performance of the meta heuristic algorithm is evaluated through compare with optimal solutions using randomly generated several examples.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.412-414
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• 2007

In motor driving, one of the most important consideration is the load characteristic and variation. Generally, the motor drive should be made enough for the current by load variation, and it should be controlled by the load weight. However, the drum washing machine's load variation is irregular and large. Therefore, we want to make the motor drive that considering this load pattern, this paper describes the drum washing machine's load pattern modeling by the mathematical theory.

• Journal of Korea Society of Industrial Information Systems
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• v.5 no.3
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• pp.51-55
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• 2000

It is automation of manufacturing process that improve productivity, quality level and delivery times in manufacturing environment. Epoxy injection process is very critical process of manufacturing electronic lighter and then controling the quantity of epoxy fluid is another critical factor of them. As development of epoxy injection machine, the product goal is accomplished and maximize the profit of company. The object of this study is implement the mathematical equation to practical examination with this machine.

• Journal for History of Mathematics
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• v.15 no.1
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• pp.93-98
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• 2002

In this paper, we critically survey the mathematical Platonism in respect to its abstract, ahistorical, asocial and acultural character. The uncertainty of man's concepts is investigated with special attention to evolutionary theory, philosophical and epistemological developments regarding the cognitive unconsciousness and the embodied mind. We research into the implication of the Darwin machine theory for human consciousness and Wittegenstein's philosophy of mathematics.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.03a
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• pp.67-71
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• 1996

The dynamic equation is built by the mathematical modelling. The modelling is composed of various components used for the automatic transmission of tracked vehicles. When the transmission is shifting, the shock occurs in the drivetrain. The transient torques affect the durability and reliability of the vehicle. The factor and design point are analyzed for the transmission.

• Structural Engineering and Mechanics
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• v.85 no.3
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• pp.315-335
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• 2023

Limited studies are available on the mathematical estimates of the compressive strength (CS) of glass fiber-embedded polymer (glass-FRP) compressive elements. The present study has endeavored to estimate the CS of glass-FRP normal strength concrete (NSTC) compression elements (glass-FRP-NSTC) employing two various methodologies; mathematical modeling and artificial neural networks (ANNs). The dataset of 288 glass-FRP-NSTC compression elements was constructed from the various testing investigations available in the literature. Diverse equations for CS of glass-FRP-NSTC compression elements suggested in the previous research studies were evaluated employing the constructed dataset to examine their correctness. A new mathematical equation for the CS of glass-FRP-NSTC compression elements was put forwarded employing the procedures of curve-fitting and general regression in MATLAB. The newly suggested ANN equation was calibrated for various hidden layers and neurons to secure the optimized estimates. The suggested equations reported a good correlation among themselves and presented precise estimates compared with the estimates of the equations available in the literature with R²= 0.769, and R² =0.9702 for the mathematical and ANN equations, respectively. The statistical comparison of diverse factors for the estimates of the projected equations also authenticated their high correctness for apprehending the CS of glass-FRP-NSTC compression elements. A broad parametric examination employing the projected ANN equation was also performed to examine the effect of diverse factors of the glass-FRP-NSTC compression elements.

• Journal of the Institute of Convergence Signal Processing
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• v.21 no.3
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• pp.121-126
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• 2020

Sound-based machine fault diagnosis is the automatic detection of abnormal sound in the acoustic emission signals of the machines. Conventional methods of using mathematical models were difficult to diagnose machine failure due to the complexity of the industry machinery system and the existence of nonlinear factors such as noises. Therefore, we want to solve the problem of machine fault diagnosis as a deep learning-based image classification problem. In the paper, we propose a CNN-based automatic machine fault diagnosis method using Spectrogram images. The proposed method uses STFT to effectively extract feature vectors from frequencies generated by machine defects, and the feature vectors detected by STFT were converted into spectrogram images and classified by CNN by machine status. The results show that the proposed method can be effectively used not only to detect defects but also to various automatic diagnosis system based on sound.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.4
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• pp.467-478
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• 2003

Automotive shock absorber may not be regarded as only one(simple) damping machine because it is composed of many components, and shows non-linear damping characteristics. No matter how advanced form of shock absorber is developed, the oil shock absorber can not be neglected. because their structures are based on the oil shock absorber. Therefore it is essential to accurately analyze the dynamic characteristics of oil shock absorber. It stands mainly roi damper valve tuning which nowadays is still exhaustively done by means of ride work. In this study, damping mechanism and dynamic characteristics for oil shock absorber of twin tube type are analyzed, based on the mathematical model considering internal flow and pressure. For the reliability of numerical prediction. the database is constructed within the limit of adequate reliability. Finally, the programmed system that gives out necessary specification by inputting damping specification and tolerance is to be constructed.