• Journal of the Korean Society of Industry Convergence
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• 제26권4_2호
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• pp.585-589
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• 2023

Unlike general carbon steel, stainless steel's mechanical properties change depending on the content of chromium and nickel. In this study, since stainless steel for high-temperature pressure container parts is used as shafts, the fatigue strength and fatigue limit of the materials were evaluated using a rotational bending fatigue test. Meanwhile, fatigue analysis was conducted under the same conditions as the specimen for structural analysis and fatigue analysis of stainless steel for high-temperature pressure container parts. Using the fatigue analysis results, we tried to derive the life of the material and the safety factor for each part. As a result of performing a fatigue test by processing a specimen for the fatigue test of A182 F6A stainless steel, the fatigue limit was 548 MPa. The ratio between the tensile strength and fatigue limit of the material was 0.545, representing 54.5% of the tensile strength.

• Journal of the Korean Society of Groundwater Environment
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• 제6권2호
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• pp.87-94
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• 1999

This study is providing Modified DRASTIC Model to which lineament density and land use are added as additional factors using geographic infomation system(GIS). and then to evaluate groundwater contamination potential of Pyungtek-Gun area in Kyunggi-Do. In this study. the reason for using additional factors is because. in case of lineament density. when we consider that most of aquifer is bedrock aquifer in hydrogeologic environment of the Korea, lineament is very important to flow of groundwater and contamination material. and because land use can reflect indirectly impact of point or non_point source in study area. For statistical analysis. vector coverage per each factor is converted to grid layer and after each correlation coefficient between factors, covariance, variance. eigenvalue and eigenvector by principal component analysis of 3 direction. are calculated. correlation between factors is analyzed. Also after correlation coefficients between general DRASTIC layer and rated lineament density layer and between general DRASTIC layer and rated land use layer are calculated. final modified DRASTIC Model is constructed by using them with each weighting. when modified DRASTIC Model was compared with general DRASTIC Model, comtamination potential in modified DRASTIC Model is fairly detailed and consequently. vulnerable area which has high contamination potential could be presented concretly.

• Journal of Korean Society of Steel Construction
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• 제9권4호통권33호
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• pp.557-578
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• 1997

The objective of the study in this paper was to develop a beam-column element to model members with purely flexural yielding, as well as members with yielding under combined flexure and axial force during severe earthquake ground motins. The developed element can be considered as an one-component series hinge type model. It has the capability to model plastic axial deformation and changes in axial stiffness, and employs hardening rules to handle monotonic, cyclic or arbitrary loading. In general, when compared to experimental results and fiber model predictions, the element showed significantly better performance than the bilinear hinger model and could properly model the beam-column behavior of bare steel members in moment resisting frames. The developed element can more accurately predict local deformation demands and overall responses of structural systems under earthquake loadings than the bilinear hinge element.

• Journal of Dental Anesthesia and Pain Medicine
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• 제24권4호
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• pp.273-283
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• 2024

Background: This study evaluated the effect of remimazolam and propofol on changes in autonomic nerve activity caused by surgical stimulation during orthognathic surgery, using power spectrum analysis of blood pressure variability (BPV) and heart rate variability (HRV), and their respective associations with cardiovascular fluctuations. Methods: A total of 34 patients undergoing Le Fort I osteotomy were randomized to the remimazolam (Group R, 17 cases) or propofol (Group P, 17 cases) groups. Observables included the low-frequency component of BPV (BPV LF; index of vasomotor sympathetic nerve activity), high-frequency component of HRV (HRV HF; index of parasympathetic nerve activity), balance index of the low- and high-frequency components of HRV (HRV LF/HF; index of sympathetic nerve activity), heart rate (HR), and systolic blood pressure (SBP). Four observations were made: (1) baseline, (2) immediately before down-fracture, (3) down-fracture, and (4) 5 min after down-fracture. Data from each observation period were compared using a two-way analysis of variance with a mixed model. A Bonferroni multiple comparison test was performed in the absence of any interaction. One-way analysis of variance followed by Tukey's multiple comparisons test was performed when a significant interaction was observed between time and group, with P < 0.05 indicating statistical significance. Results: Evaluation of autonomic nerve activity in comparison with baseline during down-fracture showed a significant increase in BPV LF (P < 0.001), an increasing trend in HRV LF/HF in Group P, and an increasing trend in HRV HF in Group R. There were no significant differences in HR or SBP between the two groups. Conclusion: During down-fracture of Le Fort I osteotomy, sympathetic nerve activity was predominant with propofol anesthesia, and parasympathetic nerve activity was predominant with remimazolam anesthesia.

• Journal of Korean Society of Rural Planning
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• 제15권3호
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• pp.23-32
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• 2009

The purpose of this research was to evaluate rural housing environment through evaluation of the two parties, public officials, the interest group and residents, the beneficiaries surveying general understanding and measuring difference in understanding between public officials and residents. Through the difference in understanding, this study was to propose effective promotion method and desirable direction of rural housing environment. For progress hereafter, by seeking active involvement of residents, this study proposed possible renewal plan of residential environment. Process of this study was first, research documents to examine several rural housing environment related promotions, and several analysis techniques like principal component analysis, multiple regression analysis used to understand different ideas Opinion of Public Officials and Inhabitants. Then take surveys of residents living in renewal zone, and surveys of public officials of borough, which already performed renewal projects to evaluate comprehensively as either residents' or administrators' view.

• The Journal of the Convergence on Culture Technology
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• 제7권3호
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• pp.481-486
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• 2021

Machine learning algorithms adopt criterion function as a key component to measure the quality of their model derived from data. Cluster analysis also uses this function to rate the clustering result. All the criterion functions have in general certain types of favoritism in producing high quality clusters. These clusters are then described by attributes and their values. Category utility and partition utility play an important role in cluster analysis. These are fully analyzed in this research particularly in terms of how they are related to the favoritism in the final results. In this research, several data sets are selected and analyzed to show how different results are induced from these criterion functions.

• Journal of the Institute of Electronics Engineers of Korea SP
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• 제48권5호
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• pp.84-95
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• 2011

In this paper, we present a deblocking algorithm that removes grid and staircase noises, which are called "blocking artifacts", occurred in the compressed satellite images. Particularly, the given satellite images are compressed with equal quantization coefficients in row according to region complexity, and more complicated regions are compressed more. However, this approach has a problem that relatively less complicated regions within the same row of complicated regions have blocking artifacts. Removing these artifacts with a general deblocking algorithm can blur complex and undesired regions as well. Additionally, the general filter lacks in preserving the curved edges. Therefore, the proposed algorithm presents an adaptive filtering scheme for removing blocking artifacts while preserving the image details including curved edges using the given quantization step size and content analysis. Particularly, WLFPCA (weighted lowpass filter using principle component analysis) is employed to reduce the artifacts around edges. Experimental results showed that the proposed method outperforms SA-DCT in terms of subjective image quality.

• The Journal of the Korea Contents Association
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• 제18권5호
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• pp.592-599
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• 2018

The purpose of this study is to examine whether the participation of lifelong learning activities of the elderly is a part of the self - The questionnaire consisted of 12 items of general characteristics, 5 items of lifelong education, 6 items of volunteer activity, 15 items of life satisfaction, and 10 items of self - integration. The subjects of this study were 300 elderly people aged 60 or older living in Seoul, Gyeonggi - do, and Incheon, and participated in lifelong educational institutions such as the elderly welfare center, elderly university, and ward. As a method of analysis, the structural equation model of AMOS 22.0 was applied. The results obtained by applying the structural equation analysis are as follows. First, general characteristics were tested and the reliability of the items was tested. The reliability of the items, predictability, accuracy, and validity were analyzed by principal component analysis. Second, the research hypothesis was verified by verifying the fit of measurement variables through participation factor of lifelong education, self - integration, life satisfaction, and voluntary service. Statistical analysis was performed using the SPSS WIN 22.0 and Amos 22.0 programs.

• Bulletin of the Society of Naval Architects of Korea
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• 제27권4호
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• pp.67-71
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• 1990

This study is concerned with the optimum design of stiffened cylindrical members frequently found in floating offshore platforms with constraints on reliability. Minimised is the expected total cost which is composed of the structural cost and the expected failure cost. Some design requirements drawn from variotus design codes are also considered as constraints. Reliability of critical component in a structure only is considered in this paper and the system failure is discarded since the probability of system failure is in general much smaller than the probability of component failure and it is very difficult to evaluate the cost due to system failure. Ultimate strength only is considered and not the fatigue strength. Several parametric studies are illustrated and the optimum solutions for different strength models which are now in use for the design of stiffened cylinders are derived to show the optimum designs against different strength models for the same type of structural component. The present results lead to the important conclusions relating to the posibility of more cost saving in the design of such structure through the reliability-based optimisation process.

• Journal of the Korean Society of Industry Convergence
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• 제7권4호
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• pp.377-382
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• 2004

This research was about implementing STEP for data exchange among different commercial package(CAD system). STEP was used to share CAD data as follows. ST-Developer implement Solid model was used with a physical file of STEP and represented in a CAD system. And then STEP conversion utility was used to make a neutrality format form in a component modeling. Analysis of Solid model was made possible for CAD system to read in and analyzed Solid model. This research are summarized as follows 1. A basis Model development used Visual C++ for a neutrality data of a programming interface general-use CAD system, and produced Box and Cylinder to a physical file, the result was implemented this in a programming interface to general-use CAD system, it is represented in CAD system as identical one modeling object. 2. STEP was used in different CAD system to utilize to its of each CAD system maximum, CATIA V5R9 user was able to analyze MDT 6 Modeling Arm. 3. STEP was used able to interpret and remodel the existing Solid model.