• Journal of Electrical Engineering and Technology
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• v.4 no.1
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• pp.43-48
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• 2009

The purpose of the this paper is to make decision of the maintenance priority of power distribution system using Time-Varying Failure Rate(TVFR) with interruption cost. This paper emphasizes the practical use of the reliability indices and interruption cost. To make a decision of maintenance priority on power distribution system equipment, the quantification of the reliability level should be represented as a cost. In this paper, the TVFR of power distribution system equipment applied in this paper utilizes analytic method to use the historical data of KEPCO. From this result, the sensitivity analysis on TVFR of equipment was done for the priority, which represents that high priority of the equipment has more effect on system reliability, such as SAIDI or SAIFI, than other equipment. By this priority, the investment plan is established. In this result, customer interruption cost(CIC) could be extracted, and CIC is used as weighting factor to consider a importance of customer. After that, the result calculated the proposal method in this paper is compared with other priority method, such as lifetime, failure rate or only sensitivity.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.4_2
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• pp.603-609
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• 2022

Bottom hole assembly(BHA) is a key component of the drilling system, consisting of various components and tools(including the drill bit and mud motor) which operate at the bottom of the wellbore and physically drill the rock. This paper investigates the dynamic characteristics of the mud motor which is a drilling propulsion tool. And computational structural analysis is performed to calculate the von-Mises stress and the safety factor of components constituting the mud motor. In this process, the field test data of onshore drilling are used for analysis.

• Korean Journal of Construction Engineering and Management
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• v.14 no.2
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• pp.56-64
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• 2013

New construction technologies, especially automated equipment, are rarely deployed on a construction site where many accidents and claims occur. This study analyzed and derived impact factors for technology adoption to improve the chance of adopting automated construction equipment to the field. First, impact factors were classified into functional and non-functional factors. Then the functional factors were divided into usability and functionality factors, and the non-functional factors into cost, construction property, and organization factors. Next, the importance and realization possibility of each impact factor were analyzed through a survey with experts. Usability and functionality were analyzed to have the highest importance and realization possibility. Lastly, the differences between construction companies and equipment development companies in the importance and realization possibility of each factor were analyzed. Construction companies recognized previous relationship, operator's attitude, members' will, and construction quality more important than equipment development companies.. The equipment development companies should consider these differences between the view of construction companies and that of equipment development companies on the impact factors. The result of this study can be used as a basis for evaluating for automated construction equipment in the preliminary development phase.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.6
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• pp.767-775
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• 2018

To develop and check a Radar Processor Unit, checking the function and performance of the requirement is very important factor in developing Radar. General methods for verifying the Radar is simulation test, environment linkage test and field operation test, firstly, in case of requirement analysis phase, verify Radar algorithm and design by using mathematical method based simulation test method, and secondly, in case of unit test and integrated test phase, Test Equipment is set to simulate radar environment in the lab to verify radar function and performance. Lastly, field operation test phase is carried out to confirm the function and performance after it is mounted on the actual equipment. To successfully develop Radar Processor Unit, using the method of field operation test method after sufficient test cases are tested in radar environmental interlocking method in order to save cost and testing period and because of this reason, development of the Radar Processor Unit Test Equipment is becoming very important factor. In this paper, we introduce the concept of test equipment development and important factors in test equipment, which are target simulation, data processing and device interlocking.

• Culinary science and hospitality research
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• v.13 no.3
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• pp.166-174
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• 2007

The purpose of this paper is to show how job satisfaction and job immersion are influenced by kitchen equipment and layouts. For verifying the credibility and availability of the results, the methods of inter-relational and factor analyses are carried out, based on 214 collected data from the questionnaire answered by employees involved in six 5-star hotel kitchens around Seoul area. Through the process of data coding and SPSS Win 12.0 program, those collected data are verified with a correlation analysis after having been carried out with frequency, factor and creditability analyses. The results are in the followings: kitchen equipment has a significant effect on job immersion as well as on job satisfaction while the kitchen layouts also give a desirable impact on job immersion and job satisfaction. In addition to them, the results show that job satisfaction also has an effect on job immersion. It is concluded that good kitchen equipment and layouts make kitchen workers turn to job immersion and satisfaction more, which will consequently have good effects on business.

• Journal of the Earthquake Engineering Society of Korea
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• v.24 no.3
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• pp.123-128
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• 2020

Analysis of the 2016 Gyeongju earthquake and the 2017 Pohang earthquake showed the characteristics of a typical high-frequency earthquake with many high-frequency components, short time strong motion duration, and large peak ground acceleration relative to the magnitude of the earthquake. Domestic nuclear power plants were designed and evaluated based on NRC's Regulatory Guide 1.60 design response spectrum, which had a great deal of energy in the low-frequency range. Therefore, nuclear power plants should carry out seismic verification and seismic performance evaluation of systems, structures, and components by reflecting the domestic characteristics of earthquakes. In this study, high-frequency amplification factors that can be used for seismic verification and seismic performance evaluation of nuclear power plant systems, structures, and equipment were analyzed. In order to analyze the high-frequency amplification factor, five sets of seismic time history were generated, which were matched with the uniform hazard response spectrum to reflect the characteristics of domestic earthquake motion. The nuclear power plant was subjected to seismic analysis for the construction of the Korean standard nuclear power plant, OPR1000, which is a reactor building, an auxiliary building assembly, a component cooling water heat exchanger building, and an essential service water building. Based on the results of the seismic analysis, a high-frequency amplification factor was derived upon the calculation of the floor response spectrum of the important locations of nuclear power plants. The high-frequency amplification factor can be effectively used for the seismic verification and seismic performance evaluation of electric equipment which are sensitive to high-frequency earthquakes.

• Journal of the Korean Institute of Landscape Architecture
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• v.39 no.1
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• pp.84-95
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• 2011

The purpose of this study is to increase the usage of satisfaction of outdoor exercise equipment installed at parks when plans and designs are made for renovation or formation of parks. In order to do so, the study surveyed and analyzed the usage satisfaction of 150 men and women who use outdoor exercise equipment in neighborhood parks located in Dongtan New Town. There were four factors that affect the variables of usage satisfaction. They can be defined as the main facility factor, awning factor, maintenance factor, and additional facility factor. From the result regression analysis of the total satisfaction rate and the factors, the main facility factor was the most influential of the variables. This could indicate that the facility factor affects the satisfactory rate of outdoor exercise equipment. This research is done only with the examples of neighborhood parks, so it limits the possibility of analysis of seasonal use. It is necessary to conduct analysis research of parks which installed many outdoor exercise equipment, such as a vest-pocket park, children's garden, and pedestrian/urban/metropolitan neighborhood parks.

• Design & Manufacturing
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• v.14 no.4
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• pp.58-64
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• 2020

Lately, the development of the semiconductor industry has led to the miniaturization of electronic devices. Therefore, semiconductor wafers of very thin thickness that can be used in Multi-Chip Packages are required. There is active research on the backgrinding process to reduce the thickness of the wafer. The backgrinding process polishes the backside of the wafer, reducing the thickness of the wafer to tens of ㎛. The equipment that performs the backgrinding process requires ultra-precision. Currently, there is no full auto backgrinding equipment in Korea. Therefore, in this study, ultra-precision backgrinding equipment was designed. In addition, finite element analysis was conducted to verify the equipment design validity. The deflection and structural stability of the backgrinding equipment were analyzed using finite element analysis.

• Journal of Drive and Control
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• v.19 no.1
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• pp.34-42
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• 2022

Hydrostatic transmission (HST) comprises rotary parts, shafts, valve plate, swashplate, and servo pistons. Ensuring structural stability of each part of an HST has a significant impact on product safety. In this study, the structural stability of HST in agricultural machinery and industrial vehicles was analyzed using ANSYS software. For conservative evaluation, high-pressure conditions (35.5 MPa and 2 MPa pilot pressure) were applied as load conditions. The number of grids used in the calculations ranged from 0.4 to 0.8 million depending on modeling requirements. Structural analysis was performed for essential parts and safety factor was analyzed. All major parts of HST had a safety factor of ≥ 1.5. Thus, they were judged to be structurally safe. This study provides important information for designing an HST system.

• Structural Engineering and Mechanics
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• v.41 no.1
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• pp.25-41
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• 2012

Kriging surrogate model provides explicit functions to represent the relationships between the inputs and outputs of a linear or nonlinear system, which is a desirable advantage for response estimation and parameter identification in structural design and model updating problem. However, little research has been carried out in applying Kriging model to crack identification. In this work, a scheme for crack identification based on a Kriging surrogate model is proposed. A modified rectangular grid (MRG) is introduced to move some sample points lying on the boundary into the internal design region, which will provide more useful information for the construction of Kriging model. The initial Kriging model is then constructed by samples of varying crack parameters (locations and sizes) and their corresponding modal frequencies. For identifying crack parameters, a robust stochastic particle swarm optimization (SPSO) algorithm is used to find the global optimal solution beyond the constructed Kriging model. To improve the accuracy of surrogate model, the finite element (FE) analysis soft ANSYS is employed to deal with the re-meshing problem during surrogate model updating. Specially, a simple method for crack number identification is proposed by finding the maximum probability factor. Finally, numerical simulations and experimental research are performed to assess the effectiveness and noise immunity of this proposed scheme.