• Ocean and Polar Research
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• v.33 no.3
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• pp.291-301
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• 2011

To investigate major factors controlling variations in water quality, principal component analysis and cluster analysis were used to analyze data sets of 12 parameters measured at 23 sampling stations of Jinhae Bay during winter and spring. Principal component analysis extracted three major factors controlling variations of water quality during winter and spring. In winter, major factors included freshwater input, polluted material input, and biological activity. Whereas in spring they were polluted material input, freshwater input, and suspended material input. The most distinct difference in the controlling factors between winter and spring was that the freshwater input was more important than the polluted material input in winter, but the polluted material input was more important than the freshwater input in spring. Cluster analysis grouped 23 sampling stations into four clusters in winter and five clusters in spring respectively. In winter, the four clusters were A (station 5), B (stations 1, 2), C (station 4), and D (the remaining stations). In spring, the five clusters included A (station 5), B (station 1), C (station 3), D (station 6), and E (the remaining stations). Intensive management of the water quality of Masan and Hangam bays could improve the water quality of Jinhae Bay since the polluted materials were mainly introduced into Jinhae Bay through Masan and Hangam bays.

• Journal of Korean society of Dental Hygiene
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• v.9 no.3
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• pp.403-414
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• 2009

Objectives : This research aimed at investigating middle school students' knowledge and behavior of oral hygiene according to the knowledge level of parents on this ground, provide basic data for establishing a more effective school and home oral hygiene education program for students. Methods : Students were selected from four secondary schools in J city by convenience sampling, which is non probability sampling; then, the final analysis was performed on 272 self-administered questionnaires. For statistical analysis, SPSS 10.0 for Windows was used to carry out frequency analysis and chi-square test at the 0.05 significance level in determining statistical significance. Results : 1. 50.0% had periodontal disease caused by 'weak periodontal', in the case of the father of academic ability was middle school graduated. 2. Showed lowly what is behavior prevention as regularly oral examination for the oral health, in the case of the parents's academic ability was low(in the case of the mother's academic ability was middle school graduated, 34.5% received regular oral examination every three months). 3. In the case of, the father and mother of academic ability was middle school graduated showed 50%, 44.8% about the teeth never important in the life. 4. In the case of, the father and mother of academic ability was middle school graduated showed 37.5%, 31.0% about time for the tooth brushing is under 1 minute per one time. Conclusions : It's very important for middle school student's oral health that the oral health education and oral hygiene attitude in their home. especially middle school student's attitude was controlled by parents' knowledge level. This like basic data will be useful in establishing program of school oral health and individual oral hygiene attitude in their home.

• Korean Journal of Environmental Agriculture
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• v.39 no.3
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• pp.237-245
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• 2020

BACKGROUND: The closed chamber method is the most commonly used for measuring greenhouse gas emissions from upland fields. This method has the advantages of being simple, easily available and economical. However, uncertainty estimation is essential for accurate assessment of greenhouse gas emissions and verification of emission reductions. The nitrous oxide emissions from upland field is very important for the nitrogen budget in the agriculture sectors. Although assessment of uncertainty components affecting nitrous oxide emission from upland field is necessary to take account of dispersion characteristics, research on these uncertainty components is very rare to date. This study aims at elucidation of influencing factors on measurement uncertainty of nitrous oxide concentrations measured by an automated open closed chamber method from upland field. METHODS AND RESULTS: The nitrous oxide sampling system is located in the upland field in Gyeonggi-do Agricultural Research and Extension Services (37°13'22"N, 127°02'22"E). The primary measurement uncertainty components influencing nitrous oxide concentrations (influencing factors) investigated in this research are repeatability, reproducibility and calibration in the aspects of nitrous oxide sampling and analytical instrumentation. The magnitudes of the relative standard uncertainty of each influencing factor are quantified and compared. CONCLUSION: Results of this study show what influencing factors are more important in determination of nitrous oxide concentrations measured using the automated open closed chambers located in the monitoring site. Quantifying the measurement uncertainty of the nitrous oxide concentrations in this study would contribute to improving measurement quality of nitrous oxide fluxes.

• The Journal of the Convergence on Culture Technology
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• v.5 no.2
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• pp.257-261
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• 2019

Service user satisfaction in the community service is also an important factor that leads to the improvement of the quality of the social service and the self - reliance of the service provider. The purpose of this paper is to examine the satisfaction factors affecting service continuity intentions in community service users, and provide direction and demand forecast information to improve user satisfaction and service satisfaction. In this study, the reliability test was conducted to check the reliability of each measurement tool and descriptive statistics and frequency analysis were conducted to identify the general characteristics of the study subjects. Logistic regression analysis was conducted to determine the effect of user satisfaction factors on service continuity. As a result of this study, it was confirmed that service user satisfaction in the community service is an important factor for improving the quality of social services and for the independence of service providers.

• International Journal of Reliability and Applications
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• v.2 no.3
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• pp.209-240
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• 2001

Computer-based simulation and analysis is used extensively in engineering for a variety of tasks. Despite the steady and continuing growth of computing power and speed, the computational cost of complex high-fidelity engineering analyses and simulations limit their use in important areas like design optimization and reliability analysis. Statistical approximation techniques such as design of experiments and response surface methodology are becoming widely used in engineering to minimize the computational expense of running such computer analyses and circumvent many of these limitations. In this paper, we compare and contrast five experimental design types and four approximation model types in terms of their capability to generate accurate approximations for two engineering applications with typical engineering behaviors and a wide range of nonlinearity. The first example involves the analysis of a two-member frame that has three input variables and three responses of interest. The second example simulates the roll-over potential of a semi-tractor-trailer for different combinations of input variables and braking and steering levels. Detailed error analysis reveals that uniform designs provide good sampling for generating accurate approximations using different sample sizes while kriging models provide accurate approximations that are robust for use with a variety of experimental designs and sample sizes.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.3_4 s.141
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• pp.391-402
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• 2005

Tile purposes of this study were to find out any significant relations among body image, needs for body modification, self concept, and some selected clothing behaviors of two age group females using social comparison theory as the research background. The sampling method was a convenient sampling, and the subjects were 56 females aged from 20 to 24 years and 54 females aged from 40 to 49 years. The quasi-experiment and survey were conducted from May 1 to June 30, 2002. The results of tile study were as follows. First, the perceptual body image is more important than measured body size and ideal body size in body image. Apart from measurement instrument, people who perceived slim had higher self concept, exhibition and conformity of clothing. Second, there were significant differences between the two age groups(twenties and forties) in needs for plastic modification, self concepts and clothing behaviors. The younger age group exhibited higher need for modification than the older age group and the younger group also showed higher self concept, higher interests in clothing and fashion, more exhibition tendency and conformity to clothing.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.1
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• pp.124-130
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• 2009

Estimating genetic interaction effects in animal genomics would be one of the most challenging studies because the phenotypic variation for economically important traits might be largely explained by interaction effects among multiple nucleotide sequence variants under various environmental exposures. Genetic improvement of economic animals would be expected by understanding multi-locus genetic interaction effects associated with economic traits. Most analyses in animal breeding and genetics, however, have excluded the possibility of genetic interaction effects in their analytical models. This review discusses a historical estimation of the genetic interaction and difficulties in analyzing the interaction effects. Furthermore, two recently developed methods for assessing genetic interactions are introduced to animal genomics. One is the restricted partition method, as a nonparametric grouping-based approach, that iteratively utilizes grouping of genotypes with the smallest difference into a new group, and the other is the Bayesian method that draws inferences about the genetic interaction effects based on their marginal posterior distributions and attains the marginalization of the joint posterior distribution through Gibbs sampling as a Markov chain Monte Carlo. Further developing appropriate and efficient methods for assessing genetic interactions would be urgent to achieve accurate understanding of genetic architecture for complex traits of economic animals.

• ETRI Journal
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• v.40 no.2
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• pp.237-245
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• 2018

The Distributed Modulated Wideband Converter (DMWC) is a networking system developed from the Modulated Wideband Converter, which converts all sampling channels into sensing nodes with number variables to implement signal undersampling. When the number of sparse subbands changes, the number of nodes can be adjusted flexibly to improve the reconstruction rate. Owing to the different attenuations of distributed nodes in different locations, it is worthwhile to find out how to select the optimal sensing node as the sampling channel. This paper proposes the spectrum sensing of DMWC based on a Markov random field (MRF) to select the ideal node, which is compared to the image edge segmentation. The attenuation of the candidate nodes is estimated based on the attenuation of the neighboring nodes that have participated in the DMWC system. Theoretical analysis and numerical simulations show that neighboring attenuation plays an important role in determining the node selection, and selecting the node using MRF can avoid serious transmission attenuation. Furthermore, DMWC can greatly improve recovery performance by using a Markov random field compared with random selection.

• Computational Structural Engineering
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• v.4 no.2
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• pp.111-117
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• 1991

The analysis method calculating the mean and standard deviation for the eigenvalue of complicated structures in which the limit state equation is implicitly expressed is formulated and applied to the buckling analysis by combining probabilistic finite element method with direct differential method which is a kind of sensitivity analysis technique. Also, the probability of buckling failure is calculated by combining classical reliability techniques such a MVFOSM and AFOSM. As random variables external load, elastic modulus, sectional moment of inertia and member length are chosen and Parkinson's iteration algorithm in AFOSM is used. The accuracy of the results by this study is verified by comparing the results with the crude Monte Carlo simulation and Importance Sampling Method. Through the case study of some structures the important aspects of buckling reliability analysis are discussed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.2
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• pp.172-178
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• 2016

The location template matching (LTM) method is a technique of identifying an impact location on a structure, and is often applied to structural health monitoring and large scale human-computer interface (HCI) systems. The LTM method utilizes a certain measure of similarity between two time signals. The correlation coefficient is most widely used for this purpose, and the group delay based method is recently proposed to improve the accuracy of finding the best matching pair of signals. In practice, one of key essential consideration for implementing the LTM method is to guarantee that a sufficient number of vibration modes must be contained in the measured signal, and yet the lower sampling rate is needed for a real-time implementation. In this paper, the properties of correlation coefficient and group delay with respect to the number of vibration modes are investigated. A few important results are obtained through extensive computer simulations and experiments. If the number of vibration modes contained in the measured signal is more than four it is sufficient for the correlation based LTM method, while the group delay based LTM method requires smaller number of vibration modes.