• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.4
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• pp.142-148
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• 2008

This study aims to find the optimal cutting conditions, which are obtained by grinding condition, and the grinding characteristics and condition of constant velocity joint were investigated with respect to wheel velocity, depth of cut, feed speed. Grinding machine has been widely used in manufacturing optical reflects of metal. Such as steel are easy to be machined because of their proper material. As a result I obtained the data of grinding conditions makes good surface roughness and the optimal condition of grinding and get the mesh condition. The purpose of this study is to find the optimum grinding wheel characteristics for cutting constant velocity joint.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.368-371
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• 2008

The optimal operation condition of gasifier is one of the most important parameters to increase efficiency and reliability in IGCC plant. Also the prediction of the syngas composition and quantity must be predicted to carry out process design of the gasification plant. However, the gasifier process licensor are protective with information on process design and optimal gasifier design conditions. So, the most of process studies in the engineering company for gasification plant have carried out to look for key parameters and optimal design conditions using several prediction methods. In this paper, we present the estimated preliminary optimal operation condition of the 300MW Demonstration Entrain Flow Gasifier using Aspen Plus. The gasifier operation temperature considering slag flow was predicted by FactSage software and Annen Model.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.3
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• pp.100-107
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• 2011

To evaluate the wear characteristics of very thin ceramic coated layer, it is very important to investigate its wear process in great detail. An effective method for investigating the wear of a thin layer is the observation of wear process in microscopic detail, using in-situ system. In this study, based on the SEM Tribosystem as in-situ system, the microscopic wear mode of TiN coatings was investigated in repeated sliding. Consequently, four modes were revealed for TiN coatings: Ploughing, powder formation, flake formation and coating delimitation. Sc(Severity of contact) can clarify transition condition of those microscopic wear modes.

• Journal of Mechanical Science and Technology
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• v.15 no.9
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• pp.1268-1273
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• 2001

To successfully establish the ELID-grinding, it is important to properly select the electrolytic condition according to grinding conditions. Currently, the selection of electrolytic condition is mainly dependent on the operators experience, which is one of difficulties preventing the successful application of ELID technique. In this study, an in-process measurement system of the insulating layer using two gap sensors-a capacitance type and an eddy current type-are developed and the change of the thickness of insulating layer during ELID grinding is detected. Evaluation experiments show the possibility to control the electrolytic condition through the in-process measurement of the layer status.

• Transactions of Materials Processing
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• v.10 no.1
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• pp.67-74
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• 2001

The cold forging process to produce a long-neck flange is investigated by using model material test. The two stage process with optimum design condition is examined using plasticine, which is suitable to model steel at room temperature. The similarity theory is employed to estimate the forging load of each sequence by strict application of similarity condition between steel(AISI 1015) and plasticine material The model test results are compared with the simulation results and shows good agreement. The proper forging process with least forming energy can be resulted in $25^{\circ}$ of extrusion semi-die angle.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.4
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• pp.191-201
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• 2016

A stochastic process has been used to develop a condition-based model for preventive maintenance of armor units of rubble-mound breakwaters that can make a decision the optimal interval at which some repair actions should be performed under the perfect maintenance. The proposed cost model in this paper based on renewal reward process can take account of the interest rate, also consider the unplanned maintenance cost which has been treated like a constant in the previous studies to be a time-dependent random variable. A function for the unplanned maintenance cost has been mathematically proposed so that the cumulative damage, serviceability limit and importance of structure can be taken into account, by which a age-based maintenance can be extended to a condition-based maintenance straightforwardly. The coefficients involved in the function can also be properly estimated using a method expressed in this paper. Two stochastic processes, Wiener process and gamma process have been applied to armor stones of rubble-mound breakwaters. By evaluating the expected total cost rate as a function of time for various serviceability limits, interest rates and importances of structure, the optimal period of preventive maintenance can easily determined through the minimization of the expected total cost rate. For a fixed serviceability limit, it shows that the optimal period has been delayed while the interest rate increases, so that the expected total cost rate has become lower. In addition, the gamma process tends to estimate the optimal period more conservatively than the Wiener process. Finally, it is found that the more crucial the level of importance of structure becomes, the more often preventive maintenances should be carried out.

• Journal of applied mathematics & informatics
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• v.30 no.1_2
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• pp.71-82
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• 2012

In this paper, we first show the weak convergence of the modified Ishikawa iteration process with errors of two total asymptotically nonexpansive mappings, which generalizes the result due to Khan and Fukhar-ud-din [1]. Next, we show the strong convergence of the modified Ishikawa iteration process with errors of two total asymptotically nonexpansive mappings satisfying Condition ($\mathbf{A}^{\prime}$), which generalizes the result due to Fukhar-ud-din and Khan [2].

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1313-1314
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• 2011

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.946-949
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• 2005

It is very a time-consuming and error-prone process to obtain the optimal injection condition, which can produce good injection molding products in some operational variation of facilities, from a seed injection condition. This study proposes a new approach to search the optimal injection molding condition using a neural network and a genetic algorithm. To estimate the defect type of unknown injection conditions, this study forces the neural network into learning iteratively from the injection molding conditions collected. Major two parameters of the injection molding condition - injection pressure and velocity are encoded in a binary value to apply to the genetic algorithm. The optimal injection condition is obtained through the selection, cross-over, and mutation process of the genetic algorithm. Finally, this study compares the optimal injection condition searched using the proposed approach. with the other ones obtained by heuristic algorithms and design of experiment technique. The comparison result shows the usability of the approach proposed.

• Transactions of the Korean hydrogen and new energy society
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• v.15 no.4
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• pp.283-290
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• 2004

The single-step process for conversion of syngas to DME give higher conversion than the syngas-to-methanol process. This arises because of a synergy among the three simultaneous reaction, methanol synthesis, methanol dehydration and water gas shift reaction, in the process. we would find the optimal condition of the process which these advantages. The optimal condition of DME synthesis reaction over a commercial $Cu/Zn/Al_2O_3$ catalyst and Hybrid catalyst in a fixed bed reactor. The syngas-to-dimethyl ether conversion was examined on various reaction condition (Temperature 473~553K, $H_2/CO$ ratio 1~3, Pressure 30'50atm, GHSV 1000~4000).