• Journal of Environmental Science International
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• v.31 no.1
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• pp.61-76
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• 2022

In this study, surface particulate matter (PM_2.5) concentrations were calculated based on empirical equations using measurements of ceilometer backscatter intensities and meteorological variables taken over 19 months. To quantify the importance of meteorological conditions on the calculations of surface PM_2.5 concentrations, eight different meteorological conditions were considered. For each meteorological condition, the optimal upper limit height for an integration of ceilometer backscatter intensity and coefficients for the empirical equations were determined using cross-validation processes with and without considering meteorological variables. The results showed that the optimal upper limit heights and coefficients depended heavily on the meteorological conditions, which, in turn, exhibited extensive impacts on the estimated surface PM_2.5 concentrations. A comparison with the measurements of surface PM_2.5 concentrations showed that the calculated surface PM_2.5 concentrations exhibited better results (i.e., higher correlation coefficient and lower root mean square error) when considering meteorological variables for all eight meteorological conditions. Furthermore, applying optimal upper limit heights for different weather conditions revealed better results compared with a constant upper limit height (e.g., 150 m) that was used in previous studies. The impacts of vertical distributions of ceilometer backscatter intensities on the calculations of surface PM_2.5 concentrations were also examined.

• Korean Journal of Remote Sensing
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• v.40 no.4
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• pp.387-396
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• 2024

Most very high-resolution (VHR) satellite images provide rational polynomial coefficients (RPC) data to facilitate the transformation between ground coordinates and image coordinates. However, initial RPC often contains geometric errors, necessitating correction through matching with ground control points (GCPs). A GCP chip is a small image patch extracted from an orthorectified image together with height information of the center point, which can be directly used for geometric correction. Many studies have focused on area-based matching methods to accurately align GCP chips with VHR satellite images. In cases with seasonal differences or changed areas, edge-based algorithms are often used for matching due to the difficulty of relying solely on pixel values. However, traditional edge extraction algorithms,such as canny edge detectors, require appropriate threshold settings tailored to the spectral characteristics of satellite images. Therefore, this study utilizes deep learning-based edge information that is insensitive to the regional characteristics of satellite images for matching. Specifically,we use a pretrained pixel difference network (PiDiNet) to generate the edge maps for both satellite images and GCP chips. These edge maps are then used as input for normalized cross-correlation (NCC) and relative edge cross-correlation (RECC) to identify the peak points with the highest correlation between the two edge maps. To remove mismatched pairs and thus obtain the bias-compensated RPC, we iteratively apply the data snooping. Finally, we compare the results qualitatively and quantitatively with those obtained from traditional NCC and RECC methods. The PiDiNet network approach achieved high matching accuracy with root mean square error (RMSE) values ranging from 0.3 to 0.9 pixels. However, the PiDiNet-generated edges were thicker compared to those from the canny method, leading to slightly lower registration accuracy in some images. Nevertheless, PiDiNet consistently produced characteristic edge information, allowing for successful matching even in challenging regions. This study demonstrates that improving the robustness of edge-based registration methods can facilitate effective registration across diverse regions.

• Journal of Information Processing Systems
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• v.9 no.2
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• pp.333-348
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• 2013

Mobile authentication/identification has grown into a priority issue nowadays because of its existing outdated mechanisms, such as PINs or passwords. In this paper, we introduce gait recognition by using a mobile accelerometer as not only effective but also as an implicit identification model. Unlike previous works, the gait recognition only performs well with a particular mobile specification (e.g., a fixed sampling rate). Our work focuses on constructing a unique adaptive mechanism that could be independently deployed with the specification of mobile devices. To do this, the impact of the sampling rate on the preprocessing steps, such as noise elimination, data segmentation, and feature extraction, is examined in depth. Moreover, the degrees of agreement between the gait features that were extracted from two different mobiles, including both the Average Error Rate (AER) and Intra-class Correlation Coefficients (ICC), are assessed to evaluate the possibility of constructing a device-independent mechanism. We achieved the classification accuracy approximately $91.33{\pm}0.67%$ for both devices, which showed that it is feasible and reliable to construct adaptive cross-device gait recognition on a mobile phone.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.19 no.4
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• pp.483-492
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• 2012

Purpose: This study was done to identify the relationship of perceived health status, leisure satisfaction, loneliness and life satisfaction and to identify predictors of life satisfaction for elders. Method: The research design for this study was a descriptive survey design using a convenience sample. Data collection was done using self-report questionnaires with 297 elders from 6 community health practitioner posts. Data were analyzed using ANOVA, t-test, Pearson correlation coefficients and hierarchical multiple regression with the SPSS Win 18.0 Program. Results: Life satisfaction had significant negative correlations with age (r=-.31, p<.001) and loneliness (r=-.73, p<.001), and positive correlations with monthly spending money (r=.44, p<.001), health status (r=.63, p<.001), and leisure satisfaction (r=.62, p<.001). The explained variance for life satisfaction was 72%. Variables of monthly spending money, health status, leisure satisfaction, and loneliness significantly predicted the degree on life satisfaction of these elders. Conclusion: Findings of this study provide a comprehensive understanding of life satisfaction and related factors for elders in Korea. However, further studies with a larger random sample and more detailed research design are necessary.

• Child Health Nursing Research
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• v.26 no.1
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• pp.55-63
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• 2020

Purpose: The purpose of this study was to evaluate the current level of sleep quality among Korean middle-school students using the Pittsburg Sleep Quality Index (PSQI), and to analyze the factors influencing sleep quality. Methods: The study used a descriptive cross-sectional design and a self-report questionnaire. The participants were 744 middle-school students. The questionnaire included the PSQI and health-related questions, such as the types of diseases they had been diagnosed with and the frequency of hospital admissions. The data were analyzed using the independent t-test, analysis of variance, Pearson correlation coefficients, and linear multiple regression. Results: The global PSQI score was 4.21, which indicated good sleep quality. The major factors that were associated with the sleep quality of middle-school students were the number of diseases they had been diagnosed with (β=.54, p=.001) and atopic dermatitis (β=.32, p=.001). In addition, asthma and the frequency of hospital admissions were significant factors influencing each component of the PSQI. Conclusion: The findings from this study suggest that sleep quality was associated with several health-related factors. Thus, nurses, school nurses, and nursing researchers may need to assess the health-related factors associated with adolescents' sleep quality as part of efforts to improve their sleep quality.

• Journal of Korean Clinical Nursing Research
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• v.18 no.2
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• pp.307-316
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• 2012

Purpose: The purpose of this study was to develop and test psychometric properties the Korean version of the End-Stage Renal Disease Adherence Questionnaire (KESRD-AQ). The ESRD-AQ, a 46-item, multidimensional, self-administrated questionnaire which was developed to assess treatment adherence to hemodialysis (HD) attendance, medications, fluid restrictions, and diet prescription among patients on maintenance hemodialysis, has been validated. Methods: The KESRD-AQ was developed by performing both translation and backtranslation. The content validity and test- retest reliability of the KESRD-AQ were evaluated by establishing item-level content validity index (I-CVI) and intra-class correlation coefficients (ICC), respectively. Construct validity was assessed by adopting a known-group analysis comparing adheres and non-adherers using Mann-Whitney U Test. Results: 41 Korean-American patients with ESRD on HD from 3 outpatient dialysis centers in California participated in the study. The KESRD-AQ showed excellent content validity (average I-CVI=.96) and test-retest reliability (ICC=.917, p=.004). The construct validity indicated that the KESRD-AQ distinguished adheres and non-adheres (p=.02~.047). Conclusion: The KESRD-AQ is a valid and reliable instrument to measure treatment adherence.

• Child Health Nursing Research
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• v.18 no.4
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• pp.157-163
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• 2012

Purpose: This study was conducted to identify the effects of life stress and depression in undergraduates on suicidal ideation. Methods: The participants in this study were 306 nursing students from three different cities. Collected data were analyzed using t-test, ANOVA, Pearson correlation coefficients, and stepwise multiple regression. Results: The mean score for life stress was 48.48, for depression, 28.59, and for suicidal ideation, 5.90. There were positive relationships between depression and life stress, suicidal ideation and life stress, and suicidal ideation and depression. The four factors of life stress, depression, school life, and gender were identified as factors influencing on suicidal ideation in undergraduates. Conclusion: The findings of this study indicate that the establishment of mental health care centers in universities, and development and implementation of nursing intervention programs for suicide prevention would be helpful.

• Nutrition Research and Practice
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• v.10 no.4
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• pp.433-441
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• 2016

BACKGROUND/OBJECTIVES: The purpose of this study was to develop a dish-based semiquantitative food frequency questionnaire (FFQ) for Korean adolescents and evaluate its reproducibility and validity. SUBJECTS/METHODS: Based on 24-hour dietary recall data from the 4th Korean National Health and Nutrition Examination Survey (KNHANES), we developed a FFQ with 71 items. From a quota sample of 160 adolescents recruited using gender and age group as stratification variables, 153 participated in the complete data collection process. The FFQ was administered to each subject twice, at an interval of 3-4 weeks, to evaluate the test-retest reliability. The validity of the FFQ was assessed relative to 8-day food record data. RESULTS: The study findings demonstrated the FFQ's satisfactory reproducibility. Spearman correlation coefficients ranged from 0.64(for ${\beta}-carotene$) to 0.81(for protein). From cross-classification analyses, the proportion of subjects in the same intake quartile was highest for protein (65.4%) and lowest for vitamin A(47.1%). With regard to validity analysis, Spearman correlation coefficients ranged from 0.27(for vitamin A and fiber) to 0.90 (for energy). The proportions of subjects in the opposite categories between the first FFQ and the 8-day food record data were generally low within the range from 0.74% (for energy and carbohydrate) to 13.2% (for ${\beta}-carotene$). CONCLUSIONS: In conclusion, the dish-based semiquantitative FFQ developed in this study can be useful for grouping Korean adolescents according to major macro- and micronutrient intakes with reasonable reproducibility and validity.

• The Journal of Korean Physical Therapy
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• v.29 no.3
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• pp.122-127
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• 2017

Purpose: The aim of this study was to investigate if the 7-item Berg balance scale (BBS) 3-point, which is a short form of the BBS (SFBBS), has compatible psychometric properties in comparison with the original BBS, and also to study the concurrent validity using a 10-meter walk test (10mWT) and a timed up and go test (TUG), which are widely used with SFBBS in clinical settings. Methods: A total of 255 patients who had experienced stroke participated in this cross-sectional study. We used results obtained from 188 patients who completed both 10mWT and TUG. The three levels in the center of the BBS were collapsed to a single level (i.e.,0-2-4) to form the SFBBS. The concurrent validity was assessed by computing the Spearman coefficients for correlation among outcome measures and in between each outcome measure and the SFBBS. As there were four outcomes, the corrected p-value for significant correlation was 0.013 (0.05/4). Results: Spearman coefficients for correlations and evaluation instruments for concurrent validity revealed significantly high validity for both of SFBBS and BBS (r=0.944). 10mWT and TUG were -0.749 and -0.770 respectively, which are in the high margin and are statistically significant (p>0.000). Conclusion: SFBBS has sound psychometric properties for evaluating patients with stroke. Thus, we recommend the use of SFBBS in both clinical and research settings.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.5078-5087
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• 2014

The aim of this study was to examine the effect of self-esteem, life satisfaction and quality of life of older people's in an elderly school program. A cross-sectional descriptive study was conducted with a survey of 269 older people in 3 elderly schools at G city from November 29, 2013 to 18. The data was analyzed using a t-test, ANOVA, Pearson's correlation coefficients and multiple regression using the SPSS WIN 20.0 program. As a research finding, an analysis of the quality of life between of the self-esteem (r=-.338, p<.001) and life satisfaction (r=-.507, p<.001) revealed significant correlations. The life satisfaction was the significant factor influencing the quality of life (${\beta}$=-.512, p< .001) and this variable explained 25.1% of the quality of life. The findings of this study should be integrated into elderly health and care services in the community and older people in elderly school programs to improve the quality of life through the systematic developments of intervention programs for health care.