• Economic Analysis
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• v.17 no.1
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• pp.131-168
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• 2011

We estimate consumer price indexes of eight major cities from 1907 to 1939, and then integrate them into a national level one. The data mainly came from the Statistical Yearbooks of the Government-General of Colonial Korea, and if necessary, we supplement them using wages and unit prices of public utility charges which are used as the price of housing and various services. We apply Laspeyres index method, and the composition ratios of consumption expenditure estimated by the commodity flow method are used as weights. The price indexes of 12 item groups as well as aggregate one are also calculated. In case of Seoul, it is possible to calculate the consumer price index from 1907 to 2009, showing a century-long pattern. This consumer price index is critical for measuring the real income and expenditure before the liberation.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.4
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• pp.447-454
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• 2023

Objective: This study aims to investigate the impact of changes in working conditions on job-related stress and musculoskeletal disorders using the results of seven surveys conducted at a single workplace from 2004 to 2022 regarding factors hazardous to the musculoskeletal system. Additionally, the study aims to propose alternative methods of investigating factors hazardous to the musculoskeletal system. Methods: A car parts manufacturing plant where the same survey was taken seven times from 2004 to 2022 was selected and the survey data was analyzed. The main contents of the survey were weekly working hours, Borg's scale, work intensity, job-related stress, and the prevalence of musculoskeletal symptoms. The statistical analysis was performed using SAS (version 9.4). Results: The results of this study are as follows. Firstly, changes in working conditions have an impact on job-related stress. Secondly, changes in working conditions have an impact on work intensity indicators. Thirdly, changes in working conditions have an impact on the prevalence of musculoskeletal symptoms. Fourthly, even with an increase in age and length of service, job-related stress and musculoskeletal symptoms were alleviated when working conditions were improved. Conclusions: In order for measures to reduce musculoskeletal disorders to be successful, working conditions must not deteriorate, and it is necessary to demand revisions to regulations, etc. to reflect these points in the investigation of hazardous factors to the musculoskeletal system.

• Biomedical Science Letters
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• v.29 no.4
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• pp.302-313
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• 2023

Y chromosomal short tandem repeat (Y-STR) markers have been developed continuously to complement forensic DNA analyses and population genetic studies. Initially, we collected data from previously reported Korean population Y-STR haplotype studies on 1133 individuals. We then conducted a marker expansion analysis using a dataset from the Y-STR Haplotype Reference Database (YHRD), covering up to 29 Y-STRs, referred to as Ymax. Additionally, we examined the impact of rapidly mutating (RM) Y-STRs included in this expanded marker set on the discrimination capacity. We observed that marker expansions both with (0.9896), and without (0.9510), RM Y-STR improved the discrimination capacity. Subsequently, we focused on 16 individuals belonging to seven distinct groups sharing identical haplotypes. These particular haplotypes had been previously identified among 476 unrelated males using 23 Y-STR markers from the PowerPlex^® Y23 System. We expanded the marker panel up to Ymax to explore how discrimination improved with an expansion of Y-STR markers for these 16 individuals. Among the expanded markers, DYS627, which had high discriminatory power, had a high mutation rate (1.10 × 10^-2) and high gene diversity (0.83). In contrast, DYF387S1 displayed high gene diversity (0.95) but a relatively low mutation rate (2.80 × 10^-3). We propose that these findings will be valuable in the selection of suitable Y-STR markers, depending on the objectives of forensic analyses. Additionally, the presence of frequently observed Y-haplotypes in Korean population will facilitate statistical interpretation in Y-STR DNA profiling.

• Journal of Korean Society on Water Environment
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• v.39 no.5
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• pp.377-389
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• 2023

Chungcheongnam-do has been measuring the flow rate and water quality of streams in the province once a month since 2011 in order to water environment policies. Based on the results, after evaluating the coefficient of variation and the tendency of the water quality trend by using the Mann-Kendall test and Sen's Slope for each stream, the streams subject to priority introduction of Total Pollution Load Management at Tributaries were selected through the Stream Grouping Method. The water quality trend analysis results for 125 streams using the Mann-Kendall test and Sen's Slope were evaluated as streams showing a tendency of deteriorating water quality Biochemical oxygen demand (BOD): 13 streams, Total Phosphorus (T-P): 16 streams). Streams with deteriorating water quality were classified into A-D groups using the Stream Grouping Method. Group A, which has a high flow rate and high water quality, is a stream that requires priority management, and was selected as a stream for introduction of Total Pollution Load Management at Tributaries. There are 7 streams that need to be introduced into the BOD category, and there are 7 streams that need to be introduced into the T-P category. In this study, based on flow and water quality monitoring data accumulated over a long period of time (2011-2022), statistical techniques are used to select watersheds in which water quality is deteriorating. Accordingly, it is expected that it will be useful in establishing a water quality improvement plan in the future.

• Archives of Craniofacial Surgery
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• v.24 no.5
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• pp.211-217
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• 2023

Background: Oral cavity cancers, the second most common type in India, are responsible for 10% of the overall cancer burden. With a recurrence rate of 30% to 40% and a 5-year survival rate of 50%, these malignancies account for substantial morbidity and mortality. Despite advances in treatment modalities, survival rates following treatment completion have not improved significantly. The present study aimed to establish specific epidemiological and pathological factors responsible for recurrence after treatment completion in buccal mucosa cancers. Methods: A retrospective analysis of the data of 116 patients treated for biopsy-proven cancers of the buccal mucosa was undertaken 1 year after treatment completion. Factors such as age, sex, education, lymphovascular invasion, extranodal extension (ENE), perineural invasion, depth of invasion, and pathological margin status were compared between patients who presented with recurrence and those who did not. Statistical significance was set at p< 0.05. Results: Of the 116 patients, 40 (34.5%) developed a recurrent disease within 1 year. The mean age of the study population was 43.3 years, and males constituted 91.4% of the included patients. Ipsilateral buccal mucosa was the commonest site of disease recurrence. Neck node metastasis, ENE, and margins of resection < 5 mm were significantly related to the recurrence of disease. However, surprisingly, lymphovascular invasion, perineural invasion, and depth of invasion > 10 mm did not show statistically significant associations. Conclusion: Neck node metastasis, ENE, and margins of resection < 5 mm were the histopathological factors associated with recurrence in cancers of the buccal mucosa.

• The Journal of Advanced Prosthodontics
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• v.15 no.6
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• pp.302-314
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• 2023

PURPOSE. The aim of this study was to classify the shapes of retromolar pads and assess their morphometric differences using a 3D model. MATERIALS AND METHODS. Two hundred fully edentulous or Kennedy Class I partially edentulous patients (400 retromolar pads) were enrolled. Scan data of the definitive mandibular casts produced through functional impressions were obtained using a 3D laser scanner. Seven parameters (transverse diameter, longitudinal diameter, transverse-contour length, longitudinal-contour length, longitudinal/transverse diameter ratio, longitudinal/transverse-contour length ratio, and angle of the retromolar pad line to the residual alveolar ridge line) were measured using image analysis software. Subsequently, the pads were classified according to the shape. Statistical analyses were performed using 95% confidence intervals. RESULTS. Classifying the retromolar pads into three shapes led to high intra-examiner reliability (Cronbach's alpha = 0.933). The pear shape was the most common (56.5%), followed by oval/round (27.7%) and triangular (15.8%) shapes. There were no significant differences between the left and right sides according to the shape and no significant differences in any parameter according to age. The transverse diameter and longitudinal/transverse diameter ratio differed between sexes (P < .05). The triangular shape had a significantly different transverse diameter, transverse-contour length, longitudinal/transverse diameter ratio, and longitudinal/transverse-contour length ratio compared with the pear and oval/round shapes (P < .05). CONCLUSION. From a clinical reliability standpoint, classifying retromolar pads into three shapes (oval/round, pear-shaped, and triangular) is effective. The differences in the sizes among the shapes were attributed to the transverse measurement values.

• Journal of Biomedical Engineering Research
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• v.44 no.5
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• pp.315-323
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• 2023

The objective of this study is to identify the selective application targets for reporting on details of supply of class 1 and 2 medical devices as part of the improvement of the reports on details of supply of medical device system, and to analyze its effectiveness. Therapeutic materials covered by health insurance and secondhand medical devices were chosen based on the transparency of health insurance coverage and the management of medical device distribution. As a result, approximately 85% of groups can be excluded from the reporting requirements compared to reporting all items under Class 1 and 2 medical devices. This is expected to enhance the efficiency of supply reporting tasks. Additionally, the information on supply details managed by the regulatory authority can be utilized for statistical analysis and periodic monitoring, serving as fundamental data for the development of medical device-related policies and research in the field of medical devices.

• Human Ecology Research
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• v.61 no.4
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• pp.565-583
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• 2023

This study sought to examine the effects of current single-parent family policies on the psychological adaptation of family members in single-parent homes, while also confirming that visitation and child support are indeed in the best interests of children in such cases. An online survey was conducted in 2021 for divorced single mothers and their children (aged 11 to 19) living in metropolitan regions (Seoul, Kyunggi, and Incheon). A total of 171 dyads, comprised of single mothers and their adolescent children, participated in this study. Using the collected data, descriptive statistical analysis and structural equation modeling were performed. The major results of this study are as follows. First, visitation with fathers was not significantly associated with self-esteem, aggression, or life satisfaction among the participating adolescent children. On the other hand, when child support was paid, aggression among adolescents was lower than when child support was not paid. Second, neither visitation nor child support was significantly associated with single mothers' levels of depression and life satisfaction. The enforcement of child support guarantees the welfare of children and conforms to the principle of promoting the best interests of minor children. Therefore, child support should be continuously encouraged and supported by agencies in accordance with current law. In order for the implementation of visitation to be in the best interest of the child, the amount and quality of visitation should be secured so that the child can still recognize their non-custodial parents as "caregivers."

• Steel and Composite Structures
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• v.49 no.2
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• pp.161-180
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• 2023

In the previous research, the axial compressive capacity models for the glass fiber-reinforced polymer (GFRP)-reinforced circular concrete compression elements restrained with GFRP helix were put forward based on small and noisy datasets by considering a limited number of parameters portraying less accuracy. Consequently, it is important to recommend an accurate model based on a refined and large testing dataset that considers various parameters of such components. The core objective and novelty of the current research is to suggest a deep learning model for the axial compressive capacity of GFRP-reinforced circular concrete columns restrained with a GFRP helix utilizing various parameters of a large experimental dataset to give the maximum precision of the estimates. To achieve this aim, a test dataset of 61 GFRP-reinforced circular concrete columns restrained with a GFRP helix has been created from prior studies. An assessment of 15 diverse theoretical models is carried out utilizing different statistical coefficients over the created dataset. A novel model utilizing the group method of data handling (GMDH) has been put forward. The recommended model depicted good effectiveness over the created dataset by assuming the axial involvement of GFRP main bars and the confining effectiveness of transverse GFRP helix and depicted the maximum precision with MAE = 195.67, RMSE = 255.41, and R2 = 0.94 as associated with the previously recommended equations. The GMDH model also depicted good effectiveness for the normal distribution of estimates with only a 2.5% discrepancy from unity. The recommended model can accurately calculate the axial compressive capacity of FRP-reinforced concrete compression elements that can be considered for further analysis and design of such components in the field of structural engineering.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.6
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• pp.763-774
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• 2023

The water availability in a river is related to the return flow of residential water. However it is still difficult to determine the exact return flow. In this study, the residential water-cycle system is defined as a process consisting of water inflow, water transfer and water outflow. The study area is Hampyeong-gun, Jeollanam-do, and is set as a single inflow to a single outflow through the water-cycle system after classification of complete and incomplete measurement points. The time-series prediction models(ARIMA model and TFM) are established with daily inflow and outflow data for 6 years. Inflow and outflow are predicted by dividing into training and test periods. As a result, both models show the feasibility of short-term prediction by deriving stable residuals and securing statistical significance, implementing the preliminary form of the water-cycle system. As a further study, it is suggested to predict the actual return flow of the target basin and efficient water operation by adding input factors and selecting the optimal model.