• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1374-1381
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• 2022

Under the influence of nuclear radiation, the reliability of steam generators (SGs) is an important factor in the efficiency and safety of nuclear power plant (NPP) reactors. Motion planning that remotely manipulates an SG mobile tube-inspection robot to inspect SG heat transfer tubes is the mainstream trend of NPP robot development. To achieve motion planning, conditional traversal is usually used for base position optimization, and then the A^* algorithm is used for path planning. However, the proposed approach requires considerable processing time and has a single expansion during path planning and plan paths with many turns, which decreases the working speed of the robot. Therefore, to reduce the calculation time and improve the efficiency of motion planning, modifications such as the matrix method, improved parent node, turning cost, and improved expanded node were proposed in this study. We also present a comprehensive evaluation index to evaluate the performance of the improved algorithm. We validated the efficiency of the proposed method by planning on a tube sheet with square-type tube arrays and experimenting with Model SG.

• Journal of Korean society of Dental Hygiene
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• v.22 no.3
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• pp.161-170
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• 2022

Objectives: This study aims to conduct in-depth research on the effect of non-surgical periodontal therapy (NSPT) with the application of a comprehensive dental hygiene care (CDHC) process, and provide basic data for the wide application of CDHC. Methods: From May 8, 2021 to September 24, 2021, mixed-methods research was conducted in 36 patients with periodontal diseases. A paired samples t-test was used to analyze the quantitative research data using IBM SPSS program(ver. 22.0; IBM Corp., Armonk, NY, USA) and qualitative research data were analyzed using the thematic analysis method. Results: With NSPT applying the CDHC process, the perception of periodontal health and self-efficacy of periodontal healthcare were increased (p<0.001). Presence of gingivitis, probing pocket depth, bleeding on probing rate, presence of subgingival calculus, and dental plaque index were reduced (p<0.001). Based on 195 meaningful statements, 26 concepts, 12 sub-themes, and 5 themes , , , and were drawn. Conclusions: The perception of periodontal health and the self-efficacy were improved, and substantial change in the clinical index. The CDHC application allowed the study participants to perceive the importance of dental care and professionalism of dental hygienists.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.244-249
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• 1998

The present paper improves the direct identification scheme based upon the equation error formulation with incomplete modal data. First, an indirect estimation technique is considered for estimating unmeasured elements of latent vectors by the combined use of a model and measured incomplete eigen vectors. It is used for estimating the other elements of eigen vectors, which are essential for identification but not available. Next an index is introduced here to indicate the quality of estimation with respect to the mode and the measured positions. A sensitivity formula for eigenvalues with respect to the unknown joint coefficient is also derived to select the modes appropriate for identification. An identification strategy is suggested to meet with practical problems with the help of the index and sensitivity formula. The index and the sensitivity are proved to be useful for selecting measurement positions and modes appropriate for identification A comprehensive simulation study is performed to test the proposed method.

• Bulletin of the Korean Mathematical Society
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• v.46 no.2
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• pp.209-227
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• 2009

We examine a unified approach of calculating the closed form solutions of option price under stochastic volatility models using stochastic calculus and the Fourier inversion formula. In particular, we review and derive the option pricing formulas under Heston and correlated Stein-Stein models using a systematic and comprehensive approach which were derived individually earlier. We compare the empirical performances of the two stochastic volatility models and the Black-Scholes model in pricing KOSPI 200 index options.

• Journal of Korea Technology Innovation Society
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• v.8 no.2
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• pp.583-604
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• 2005

The future will see all industries become technology-driven in the competitive global market place. Firms with deep technological roots and innovation strategies have some advantages. In this situation widely used scoring approach is not enough to evaluate technology's relative competitiveness and to assign relative ranking category. Therefore, a more useful and comprehensive approach, which is called technology composite index, is needed to complement and enhance the existing scoring approach. In this research, factor analysis is applied to determine the common factors and to estimate associated weights. And technology composite index is used to measure the technology's relative strength and also to assign its ranking category instead of technology scoring.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.6
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• pp.752-757
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• 2014

This paper attempts to evaluate the impact of power plant penetration on constraints of a transmission network and proposes a methodology based on risk level, which can evaluate the condition of the network and facilities intuitionally. Furthermore, based on this methodology, RLII(Risk Level Improvement Index) is proposed in order to establish comprehensive TNEP(Transmission Network Expansion Planning) from a viewpoint of ISO(Independent System Operator). In order to verify the proposed methods in this paper, real power systems in Incheon and Shiheung areas, south Korea are applied to the case study.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.3
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• pp.29-58
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• 2022

Recently, Korea has been experiencing a problem of population decline, therefore the transition to a compact spatial structure is being urged. However, what is required is not just physical compression, but a compact city that also considers connectivity, in view of the changes in today's demographic and industrial structure. From this point of view, this study measures the compressibility of domestic cities suffering from extinction risk due to low birth rates, aging population, and population decline, and examined the spatial structure characteristics. In addition to the compressibility evaluation index used in previous studies, the compressibility of six indicators (population, land use, service accessibility, transport accessibility, connectivity, and concentration) was compared and analyzed, and a comprehensive compression index was calculated. The analysis results, based on the comprehensive compression index, classified 2.3% cities in the first grade, 4.6% in the second grade, 16.09% in the third grade, 43.68% in the fourth grade, and 33.33% in the fifth grade areas. Currently, the urban characteristics affecting the compactness index differ from region to region. Therefore, it is necessary to establish measures and policies for extinction risk considering the influence of each region's compactness index. This study is meaningful in that connectivity was considered using spatial syntax, and the compactness of cities at risk of extinction was compared and analyzed quantitatively. It is expected that this study will be used as basic data to establish the direction and action strategy for extinction risk cities.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.3
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• pp.51-59
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• 2019

Purpose : To evaluate the effect of comprehensive art therapy on physical function and activities of daily living in children with cerebral palsy (CP). Methods : Ten ambulant children with diplegic (n=8) or hemiplegic (n=2) CP participated in this study. All were randomly assigned to either the art therapy group (n=5) or the control group (n=5). Both groups received physical therapy based on neurodevelopmental techniques for 20 minutes a day, 1 day a week, for a period of 12 weeks. Children in the art therapy group received additional comprehensive art therapy for 70 minutes once a week for 3 months. Tests for various measurements-Motricity Index (MI) for strength, Trunk Control Test (TCT) for trunk ability, Gross Motor Function Measure (GMFM) and Gross Motor Function Classification System (GMFCS) for gross motor function, Denver Developmental Screening Test-II (DDST-II) for developmental milestones, Functional Independence Measure of Children (WeeFIM) for abilities to complete daily activities, Leg and Hand Ability Test (LHAT) for limb function-were performed before and after treatments. Results : The upper extremity and whole extremity strengths of MI, self-care and total scores of WeeFIM, and leg and arm functions of LHAT improved significantly only for individuals in the art therapy group after the art therapy (p<.05). The value of MI after treatment was at the upper extremity and whole extremity strengths the leg function of LHAT was also significantly improved compared to the control group (p<.05). Conclusion : This study revealed that comprehensive art therapy along with physiotherapy was effective in increasing upper extremity strength and leg ability in children with CP. This suggests that comprehensive art therapy may be a useful adjunctive therapy for children with CP.

• Korean Journal of Exercise Nutrition
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• v.25 no.3
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• pp.36-43
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• 2021

[Purpose] Exercise is a key factor in preventing obesity and metabolic syndrome. Sumo wrestlers increase their body size from childhood for athletic advantage; however, the risk of metabolic syndrome in junior sumo wrestlers is undetermined. Preventive measures against pediatric obesity should be initiated during childhood to prevent obesity in adulthood, considering its high global incidence. We comparatively evaluated the risk factors for metabolic syndrome in junior sumo wrestlers and children with obesity. [Methods] We enrolled 70 male children (age 9-17 years [sumo group, n = 14] and 9-14 years [other sports and non-exercise groups, n = 28 each]) and evaluated their anthropometric parameters (height, weight, body mass index z-score, obesity rate, waist circumference, waist to height ratio) and hematological parameters (total, low-density, high-density, and non-high-density lipoprotein-cholesterol; triglycerides; plasma glucose, and glycated hemoglobin levels). [Results] The BMI z-score, obesity rate, waist circumference (p < 0.05, along with the non-exercise group), and systolic blood pressure were significantly higher and the high-density cholesterol level was lower in the sumo group than in the other sports group (p < 0.05). The waist to height ratio was significantly higher in the non-exercise group than in the other sports group (p < 0.05). No significant difference was found in other blood lipid, plasma glucose (significantly lower level than the reference range in the sumo group, p < 0.05), and glycated hemoglobin (within the reference range in all groups) levels among the three groups. [Conclusion] Junior sumo wrestlers had a larger body size and higher blood pressure than children with obesity who exercised regularly. This provides direction for future research into targeted preventive interventions against metabolic syndrome for junior sumo wrestlers with large body size.

• Journal of the Korean Society of Safety
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• v.30 no.5
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• pp.52-58
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• 2015

Although lots of safety inspection and precision safety diagnosis have been conducted on concrete retaining wall, there is no comprehensive analysis on the basis of the accumulated data associated with the statistic. Especially, the concentrated management is necessary on the evaluation items that cause critical damages for the efficient performance. In this regard, this study conducted a correlation analysis between the 18 condition evaluation items and defect index for the concrete retaining wall as well as how each item affects the final defect index as much as in the manual. As a result, correlation coefficient between sliding and overturning was 0.601, which means that they have a strong correlation, and the most influential item on defect index is the condition of drainage that scored the 0.750 correlation coefficient. In addition, as a result of regression analysis, the condition of drainage with the 0.683 correlation coefficient has a strong correlation with the defect index. If the condition evaluation items are integrated or readjusted based on the results of the statistical analysis in this study, the more efficient and accurate maintenance will be possible.