• Journal of Society of Preventive Korean Medicine
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• v.17 no.1
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• pp.181-197
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• 2013

Objectives : This study aimed to assess the differences in treatment behavior by reviewing data of a medical institution that studies treatment behavior in URI and assessing the treatment efficacy in Korea. Methods : We analyzed the behavior of medical customers and providers of upper respiratory infection medications using the NPS published by the Health Insurance Review Assessment Service. We created an operational definition for complications, and confirmed the difference in complication distribution between medical specialties. We also performed a multivariate analysis using a mixed model to elucidate the factors influencing the occurrence of complications. Results : The outcomes of analyzing factors to influence the difference in practice patterns of the diagnosing URI between the physicians are as follows; (1) Analysis of antibiotics prescriptions rate showed significant difference from medical departments (pediatrics; 49.7%, internal medicine; 54.2%, otorhinolaryngology; 69.6%, family medicine; 61.6%, general surgery; 57.5%, p<0.001). Analysis of steroid prescriptions rate showed significant difference from medical departments (pediatrics; 3.8%, internal medicine; 4.5%, otorhinolaryngology; 5.4%, family medicine; 3.0%, general surgery; 11.2%, p<0.001). (2) In patients who visited medical institutes with the common cold, the complication distribution differed according to the medical specialty, which suggests that specific complications arise depending on the particular medical specialty (p<0.001). (3) Moreover, through multivariate analysis, we found that the complication rate is higher in clinics than in hospitals, depending on the institute's size. (p<0.001; odds ratio of 4.67 in clinics than in hospitals, 95% CI 2.66-8.21) Conclusions : We observe a deviation between the behavior of patients diagnosed with URI and medication providers. This may arise from the interaction between providers and consumers, wherein the complications are associated with the choice of outpatient department and the prevention of cutting incentives. These findings suggest that the health policies should be improved to prevent inappropriate medical practice in the treatment of pediatric URI.

• Tuberculosis and Respiratory Diseases
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• v.78 no.4
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• pp.341-348
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• 2015

Background: There have been various results from studies concerning the predictors of recurrence in early-stage nonsmall cell lung cancer (NSCLC). Therefore, an accurate assessment is needed to guide effective adjuvant therapy. We investigated the predictors of a recurrence in patients with resected, early-stage NSCLC and the risk factors associated with locoregional or distant recurrence. Methods: This retrospective study was conducted on patients at the Pusan National University Hospital from January 2006 to December 2011. Patients with pathological stages I or II were included in this study, as based on the seventh edition TNM staging system. Multivariate Cox proportional hazard models were used to identify factors associated with recurrence. Results: Two hundred and forty-nine patients were included. Among them, 180 patients were stage I, and 69 were stage II. Overall, by multivariate analysis, the independent factors associated with a 5-year total recurrence were the presence of visceral pleural invasion (VPI) (p=0.018) and maximal standardized uptake values (SUVs) of tumors on positron emission tomography (PET) >4.5 (p=0.037). The VPI was the only independent risk factor associated with both locoregional and distant recurrence, in the analysis of the patterns of tumor recurrence and their risk factors. In the subgroup analysis of stage I patients, three variables (male, VPI and resection margin positive) were significantly associated with a 5-year recurrence. Conclusion: The independent factors associated with postoperative recurrence in early-stage NSCLC were as follows: PET SUV >4.5 and the presence of VPI. For patients with those factors adjuvant therapy should be recommended as a more efficacious treatment.

• Journal of Environmental Health Sciences
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• v.42 no.4
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• pp.280-292
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• 2016

Objectives: The objective of this study was to build COD regression models for the Han River and evaluate water quality. Methods: Water quality data sets for the dry season (as of January) during a four-year period (2012-2015) were collected from the database of the Han River automatic water quality monitoring stations. Statistical techniques, including combined genetic algorithm-multiple linear regression (GA-MLR) were used to build five-descriptor COD models. Multivariate statistical techniques such as principal component analysis (PCA) and cluster analysis (CA) are useful tools for extracting meaningful information. Results: The $r^2$ of the best COD models provided significant high values (> 0.8) between 2012 and 2015. Total organic carbon (TOC) was a surrogate indicator for COD (as COD/TOC) with high reliability ($r^2=0.63$ in 2012, $r^2=0.75$ for 2013, $r^2=0.79$ for 2014 and $r^2=0.85$ for 2015). The ratios of COD/TOC were calculated as 2.08 in 2012, 1.79 in 2013, 1.52 and 1.45 in 2015, indicating that biodegradability in the water body of the Han River was being sustained, thereby further improving water quality. The BOD/COD ratio supported these findings. The cluster analysis revealed higher annual levels of microorganisms and phosphorous at stations along the Hangang-Seoul and Hantangang areas. Nevertheless, the overall water quality over the last four years showed an observable trend toward continuous improvement. These findings also suggest that non-point pollution control strategies should consider the influence of upstreams and downstreams to protect water quality in the Han River. Conclusion: This data analysis procedure provided an efficient and comprehensive tool to interpret complex water quality data matrices. Results from a trend analysis provided much important information about sources and parameters for Han River water quality management.

• Korean Journal of Child Studies
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• v.9 no.1
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• pp.93-118
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• 1988

Systematic Training for Effective Parenting, developed by Dinkmeyer and McKay, is a parent education program that emphasizes social-emotional development. The present research studied the applicability of STEP to Korean mothers by examining changes in mothers' self-concept, mother's child-rearing attitudes, and children's behavior. The subjects of this study were 43 mothers of a kindergarten in Chonju City. 25 mothers were assigned to the control group and 18 mothers to the experimental group. Primary observes, consisting of 43 fathers of kindergarten children, and secondary observers, consisting of 43 Woosuk University students observed mothers' child-rearing attitudes and children's behavior. Instruments included the self-concept test by Jung Woonsik, Schaefer's Maternal Behavior Research Instrument, O Kiseon's Parent Child Relationship Test, Fear's parent questionnaire, and McKay's Adlerian Parental Assessment of Child Behavior. The mothers' child-rearing attitudes and the children's behavior are recorded by the observers and were compared with mothers' responses. The data were analyzed by MANOVA (multivariate analysis of variance), and ANOVA (analysis of variance). While the MANOVA showed no significant difference between the control and the experimental groups in changing the mothers' self-concept, differences in 5 of the 8 subfactors showed that STEP implemented positive change in the self-identity, self-satisfaction, self-behavior, personal self and family self in the experimental group. The MANOVA showed a significant difference between the two groups in changing the mothers' child-rearing attitudes. That is after participating in the STEP program, the mothers of the experimental group showed more significant progress than those of the control group. Mothers' observations of positive change in children's behavior agreed with those of the primary and secondary observers.

• Journal of the Korea Society for Simulation
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• v.16 no.4
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• pp.13-22
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• 2007

Fault detection of cycle-based signals is typically performed using statistical approaches. Univariate SPC using few representative statistics and multivariate analysis methods such as PCA and PLS are the most popular methods for analyzing cycle-based signals. However, such approaches are limited when dealing with information-rich cycle-based signals. In this paper, process fault defection method based on wavelet analysis is proposed. Using Haar wavelet, coefficients that well reflect the process condition are selected. Next, Hotelling's $T^2$ chart using selected coefficients is constructed for assessment of process condition. To enhance the overall efficiency of fault detection, the following two steps are suggested, i.e. denoising method based on wavelet transform and coefficient selection methods using variance difference. For performance evaluation, various types of abnormal process conditions are simulated and the proposed algorithm is compared with other methodologies.

• Journal of Preventive Medicine and Public Health
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• v.34 no.3
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• pp.244-252
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• 2001

Objective : Health insurers and policy makers are increasingly examining the hospital mortality rate as an indicator of hospital quality and performance. To be meaningful, a risk-adjustment of the death rates must be implemented. This study reviewed 5 severity measurement methods and applied them to the same data set to determine whether judgments regarding the severity-adjusted hospital mortality rates were sensitive to the specific severity measure. Methods : The medical records of 584 patients who underwent coronary artery bypass graft surgery in 6 general hospitals during 1996 and 1997 were reviewed by trained nurses. The MedisGroups, Disease Staging, Computerized Severity Index, APACHE III and KDRG were used to quantify severity of the patients. The predictive probability of death was calculated for each patient in the sample from a multivariate logistic regression model including the severity score, age and sex to evaluate the hospitals' performance, the ratio of the observed number of deaths to the expected number for each hospital was calculated. Results : The overall in-hospital mortality rate was 7.0%, ranging from 2.7% to 15.7% depending on the particular hospital. After the severity adjustment, the mortality rates for each hospital showed little difference according to the severity measure. The 5 severity measurement methods varied in their statistical performance. All had a higher c statistic and $R^2$ than the model containing only age and sex. There was a little difference in the relative hospital performance evaluation by the severity measure. Conclusion : These results suggest that judgments regarding a hospital's performance based on severity adjusted mortality can be sensitive to the severity measurement method. Although the 5 severity measures regarding hospital performance concurred, more often than would be expected by chance, the assessment of an individual hospital mortality rates varied by the different severity measurement method used.

• Journal of Oral Medicine and Pain
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• v.42 no.2
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• pp.29-34
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• 2017

Purpose: To evaluate aggravating factors of intermittent locking among temporomandibular joint using magnetic resonance imaging (MRI) and diagnostic criteria for temporomandibular disorder (DC/TMD) diagnosis. Methods: A retrospective analysis was conducted of 35 patients with intermittent locking history but normal intra-articular findings between September 2012 and June 2015 in Kyung Hee University Dental Hospital. A standardized DC/TMD assessment was performed on subjects with MRI findings. Clinical findings were assessed on the basis of maximum mouth opening (active & passive), self-reported habits, patients' age, gender, systemic diseases at the initial visit. First, chi square test was used to examine differences with variables and then risk factors for intermittent locking were assessed using multivariate logistic regression. Results: Self-reported bruxism was strongly associated with intermittent locking history. Conclusions: The new DC/TMD protocol is intended for use within any clinical setting and supports the full range of diagnostic activities from screening to definitive evaluation and diagnosis. Self-reported sleep bruxism has been associated with a higher likelihood of intermittent locking. Comorbidity is therefore a factor that must be assessed. It is necessary to consider the amount of contact of the teeth and the duration.

• Journal of Environmental Health Sciences
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• v.42 no.6
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• pp.353-364
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• 2016

Objectives: Determining the time activity patterns of urban populations is critical when performing an exposure assessment. The purposes of this study were to classify urban populations in Korea by their time activity patterns and to identify factors that influence these patterns. Methods: The time activity patterns of 31,634 and 20,263 individuals were obtained from two national databases collected in 2004 and 2009, respectively. The two largest metropolitan cities in Korea, Seoul and Busan, were selected for this analysis. For each city, multivariate linear regressions were performed to determine factors affecting the time spent in a residence and in transit. We also used cluster analysis to classify each urban population by activity pattern. Results: Nine distinctive activity patterns were identified in the Seoul and Busan populations, respectively, and the resulting classified population groups had specific characteristics. The identified patterns were similar for Seoul and Busan. The most significant factors affecting time spent in a residence were employment status, age, marriage status, education, and gender. Gender, education, employment status, and monthly income were significant factors affecting time spent in transit. Conclusion: These results indicate that, in addition to region, exposure scientists in Korea should consider classifying populations based on age, gender, and occupation.

• Journal of Korean Society of Rural Planning
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• v.11 no.4 s.29
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• pp.47-57
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• 2005

The goal of this research is to evaluate landscape-ecological characteristics of watersheds in the Nakdong River Basin by using Geogaphic Information System (GIS) and landscape indices for integation of spatio-temporal informations and multivariate statistical techniques for quantitative analysis of forest landscape. Fragmentation index and change matrix techniques using factor analysis and grid overlay method were used to efficiently analyze and manage huge amount of information for ecological-environmental assessment (land-cover and forest landscape patterns). According to the results based on the pattern analysis of land-cover changes using the change detection matrix between 1980s and 1990s, addition on 750km$^2$ became urbanized areas. The altered 442.04km$^2$ was agricultural areas which is relatively easy for shifting of land-use, and 205.1km$^2$ of forests became urbanized areas, and average elevation and slope of the whole altered areas were 75m and 4$^{\circ}$. On the other hand, 120km$^2$ of urban areas were changed into other areas (i.e., agricultural areas and green space), and fortunately, certain amount of naturalness had been recovered. But still those agricultural areas and fallow areas, which were previously urban areas, had high potential of re-development for urbanization due to their local conditions. According to the structural analysis of forest landscape using the landscape indices, the forest fragmentation of watersheds along the main stream of the Nakdong River was more severe than my other watersheds. Furthermore, the Nakdong-sangju and Nakdong-miryang watersheds had unstable forest structures as well as least amount of forest quantity. Thus, these areas need significant amount of forest through a new forest management policy considering local environmental conditions.

• Journal of Chest Surgery
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• v.53 no.6
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• pp.392-399
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• 2020

Background: Surgical treatment of empyema thoracis in patients with chronic kidney disease is challenging, and few studies in the literature have evaluated this issue. In this study, we aim to report the surgical outcomes of empyema and to analyze factors predicting perioperative mortality in patients with chronic kidney disease. Methods: This retrospective study included data from 34 patients with chronic kidney disease (estimated glomerular filtration rate <60 mL/min/1.73 ㎡ for 3 or more months) who underwent surgery for empyema between 2012 and 2020. An analysis of demographic characteristics and perioperative variables, including complications, was carried out. Postoperative mortality was the primary outcome measure. Results: Patients' age ranged from 20 to 74 years with a 29-to-5 male-female ratio. The majority (n=19, 55.9%) of patients were in end-stage renal disease (ESRD) requiring maintenance hemodialysis. The mean operative time was 304 minutes and the mean intraoperative blood loss was 562 mL. Postoperative morbidity was observed in 70.5% of patients (n=24). In the subgroup analysis, higher values for operative time, blood loss, intensive care unit stay, and complications were found in ESRD patients. The mortality rate was 38.2% (n=13). In the univariate and multivariate analyses, poor performance status (Eastern Cooperative Oncology Group >2) (p=0.03), ESRD (p=0.02), and late referral (>8 weeks) (p<0.001) significantly affected mortality. Conclusion: ESRD, late referral, and poor functional status were poor prognostic factors predicting postoperative mortality. The decision of surgery should be cautiously assessed given the very high risk of perioperative morbidity and mortality in these patients.