• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.3
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• pp.146-152
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• 2017

Stabilizing the operation of dual fuel diesel engines is very important. The shipbuilding industry is rapidly growing, but gear components requiring reliability are still imported from other countries. The reasoning for this is three-fold. Firstly, it is compulsory that all ships must use devices that meet the performance standards specified in the Safety of Life at Sea (SOLAS) and the convention of MARine POLlution (MAPOL) to prevent pollution caused by ships. Secondly, most ships must comply with the ship classifications specified by ship owners. Therefore, it is specified that key engine gear components must be inspected and authorized for the quality and performance specified by the Ship Register Authority. Thirdly, it is essential that devices (engine gear) for human safety in ships comply with quality standards specified in the regulations and rules by the government. The Ship Register Authority's strict quality standards and approval requirements contribute to the reduction of motivation towards new investment and technology development by device component manufacturers. Therefore, this study aims to develop a method for using infrared thermography to examine gear reliability in order to ensure gear component reliability and national competitiveness in the global market.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.8
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• pp.774-780
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• 2011

Recently, customers have been concerned about vehicle NVH depending on vehicle designing and manufacturing technologies development. In choosing vehicle, vehicle NVH is becoming the most important factor to customers. Especially, a seat is the final stage of vibration transfer path to passengers from all sources of vibration like engine, transmission and etc. And seat is the nearest component from driver's ear. For this reason, seat is the most important component that directly related to ride comfort for passengers. And driver can be influenced sensitively by BSR caused by seat. Thus, evaluating the vibration characteristics of vehicle seat and BSR caused by vehicle seat is necessary to reduce the seat BSR. The rattle noise occurred from seat has evaluated through sound source visualization and multi-dimensional spectral analysis - coherence function technique in this paper. Vibration characteristics of the seat has verified through modal test.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.10 s.181
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• pp.2597-2602
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• 2000

The most effective means of evaluating remaining life is through the creep testing of samples removed from the component. But sampling of large specimen from in-service component is actually impossible. So, sampling device and small-specimen creep tester have been applied. Sampling device has been devised to extract mechanically small samples by hemispherical, diamond -coated cutter from the surface of turbine rotor bores and thick-walled pipes without subsequent weld repairs requiring post weld heat treatment. A method of manufacturing small creep specimen, 2min gage diameter and 10min gage length, using electron beam welding to attach grip section, has been proven. Small-specimen creep tester has been designed to control atmosphere to prevent stress increment by oxidation during experiment. To determine whether the small specimens successfully reproduce the behavior of large specimens, creep rupture tests for small and large specimens have been performed at identical conditions. Creep rupture times based on small specimens have closely agreed within 5% error compared with that of large specimen. The errors in rupture time have decreased at longer test period. This comparison validates the procedure for fabricating and testing on small specimen. This technique offers potential as an efficient method for remaining life assessment by direct sampling from in -service high temperature components.

• Journal of Power System Engineering
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• v.17 no.1
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• pp.50-57
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• 2013

This describes the formulation for the free vibration of joined conical-cylindrical shells with uniform thickness using the transfer of influence coefficient. This method was developed based on successive transmission of dynamic influence coefficients, which were defined as the relationships between the displacement and the force vectors at arbitrary nodal circles of the system. The two edges of the shell having arbitrary boundary conditions are supported by several elastic springs with meridional/axial, circumferential, radial and rotational stiffness, respectively. The governing equations of vibration of a conical shell, including a cylindrical shell, are written as a coupled set of first order differential equations by using the transfer matrix of the shell. Once the transfer matrix of a single component has been determined, the entire structure matrix is obtained by the product of each component matrix and the joining matrix. The natural frequencies and the modes of vibration were calculated numerically for joined conical-cylindrical shells. The validity of the present method is demonstrated through simple numerical examples, and through comparison with the results of previous researchers.

• The Journal of Society for e-Business Studies
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• v.7 no.1
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• pp.129-140
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• 2002

To succeed in ERP construction, the purpose of ERP setup must be completed. To accomplish this end, it is required to analysis business process completely and make a plan in detail. For ERP providers', they must support a characterized ERP construction methodology and lower the construction cost by improving an ERP package by making it easy to customize. But, because imported EHP products that are supplied currently are designed for the standard and the rationality, they have a limit to support custom processes of domestic companies. On the contrary, ERP products by domestic companies are unable to support a consistent methodology of constructing ERP system. This is a main reason why much time and costs are consumed than that of an original plan. For solving the problems, ERP packages should provide a consistent process modeling methodology and a modeling tool which can support this methodology. Furthermore, customizing cost must be lowered by implementing reusable components from the process models. This Paper describes a component-based ERP Package system which has peculiar modeling tools and development tools. We describe the modeling methodology and the business component definition of the ERP system. Finally, we describe its customizing process based on these process designs and business components.

• Corrosion Science and Technology
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• v.11 no.5
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• pp.173-178
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• 2012

To manage the wall thinning of carbon steel piping in nuclear power plants, the utility of Korea has performed thickness inspection for some quantity of pipe components during refueling outages and determined whether repair or replacement after evaluating UT (Ultrasonic Test) data. When the existing UT data evaluation methods, such as Band, Blanket, PTP (Point to Point) Methods, are applied to a certain pipe component, unnecessary re-inspecting situations may be generated even though the component does not thinned. In those cases, economical loss caused by repeated inspection and problems of maintaining the pipe integrity followed by decreasing of newly inspected components may be generated. EPRI (Electric Power Research Institute) in USA has suggested several statistical methods, TPM (Total Point Method), LSS (Least Square Slope) Method, etc. to distinguish whether multiple inspecting components have thinned or not. This paper presents the analysis results for multiple inspecting components over three times based on both NAM (Near Area of Minimum) Method developed by KEPCO-E&C and the other methods suggested by EPRI.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.2
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• pp.240-247
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• 2007

This paper presents an implementation of the generator protective relay using Real Time Digital Simulator (RTDS) user defined component (UDC) model designed to facilitate the investigation and evaluation of protective relays. The UDC for RTDS is a convenient model that allows user to develop new component models and run them on the RTDS. The developed model has major features related to the development of six models such as distance, frequency, reverse power, volts per Hz, over voltage, and out-of-step relays. Also, the generator relay models have been used to support and enhance power engineering education at both the undergraduate and graduate levels. The developed model functions are verified and tested by both static test and dynamic test. The simulation results show the capabilities of the developed generator relay using RTDS UDC.

• Korean Journal of Adult Nursing
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• v.28 no.6
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• pp.619-627
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• 2016

Purpose: This study was to test a structural model of spirituality and the quality of life of stroke survivors' caregivers in order to provide guidelines for the development of intervention and strategies to improve their quality of life. Methods: Data were collected from 133 family caregivers of stroke patients who were hospitalized in C university hospital located in Seoul. Data collection using survey questionnaires was done from May, 2013 to February, 2014. Results: Fitness of the hypothetical model was appropriate. Physical component of quality of life of family caregivers is directly affected by two variables (51.5%), burden and depression. Mental component of quality of life of family caregivers is directly affected by three variables (77.6%), depression, burden, and functional dependence of patients. Depression as well as burden were directly affected by spirituality and functional dependence of patients respectively. Thus, spirituality directly affected depression and burden and indirectly affected the quality of life of family caregivers. Conclusion: Therefore, spiritual intervention to improve the stroke caregivers' quality of life might be necessary to support and strengthen their spirituality as a mediating variable that can contribute to decreasing their depression and burden.

• Journal of Mechanical Science and Technology
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• v.20 no.11
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• pp.1934-1941
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• 2006

As the operating time of heat exchangers progresses, fouling caused by water-borne deposits and the number of plugged tubes increase and thermal performance decreases. Both fouling and tube plugging are known to interfere with normal flow characteristics and to reduce thermal efficiencies of heat exchangers. The heat exchangers of Korean nuclear power plants have been analyzed in terms of heat transfer rate and overall heat transfer coefficient as a means of heat exchanger management. Except for fouling resulting from the operation of heat exchangers, all the tubes of heat exchangers have been replaced when the number of plugged tubes exceeded the plugging criteria based on design performance sheet. This paper describes a plugging margin evaluation method taking into account the fouling of shell-and-tube heat exchangers. The method can evaluate thermal performance, estimate future fouling variation, and consider current fouling level in the calculation of plugging margin. To identify the effectiveness of the developed method, fouling and plugging margin evaluations were performed at a component cooling heat exchanger in a Korean nuclear power plant.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.415.2-415.2
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• 2014

Cost-effective, robust devices for solid-state lighting industry that converts electricity to light revolutionize the current lighting industry. Phosphor materials used in these devices should be synthesized in a low-cost and effective method for use in WLEDs. In this presentation, the synthesis of Eu3+ ions doped BaMoO4 phosphor samples by a facile synthesis process for red component of WLEDs will be shown. The tetragonal phase of the host lattice was substantiated by the X-ray diffraction patterns. The morphological studies were carried out by using a field-emission scanning electron microscope and transmission electron microscope. These confirmed the formation of a shuttle like particles with perpendicular protrusions in the middle of the particle. The photoluminescence (PL) properties exhibited good emission with a high asymmetry ratio when excited with ultraviolet B wavelengths (~ 280-315 nm). The cathodoluminescence (CL) spectra showed similar results to the PL spectra, indicating the rich red emission. The results suggest that this phosphor is a good material as red region component in the development of tri-band UV excitation based WLEDs.