• The Journal of Advanced Prosthodontics
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• 제2권3호
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• pp.71-76
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• 2010

PURPOSE. The purpose of this study was to compare men with women in terms of speech intelligibility, to investigate the validity of objective acoustic parameters related with speech intelligibility, and to try to set up the standard data for the future study in various field in prosthodontics. MATERIALS AND METHODS. Twenty men and women were served as subjects in the present study. After recording of sample sounds, speech intelligibility tests by three speech pathologists and acoustic analyses were performed. Comparison of the speech intelligibility test scores and acoustic parameters such as fundamental frequency, fundamental frequency range, formant frequency, formant ranges, vowel working space area, and vowel dispersion were done between men and women. In addition, the correlations between the speech intelligibility values and acoustic variables were analyzed. RESULTS. Women showed significantly higher speech intelligibility scores than men and there were significant difference between men and women in most of acoustic parameters used in the present study. However, the correlations between the speech intelligibility scores and acoustic parameters were low. CONCLUSION. Speech intelligibility test and acoustic parameters used in the present study were effective in differentiating male voice from female voice and their values might be used in the future studies related patients involved with maxillofacial prosthodontics. However, further studies are needed on the correlation between speech intelligibility tests and objective acoustic parameters.

• 전력전자학회논문지
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• 제7권1호
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• pp.48-54
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• 2002

본 논문에서는 간접 유도가열 되는 DPH시스템과 주파수 범위가 20kHz에서 50kHz사이에서 작동되는 전압형 직렬공진 고주파인버터를 이용하여 열 기체를 발생시키는 전압형 공진형 인버터에 관하여 설명하였다. 얇은 스텐레스 판재가 서로 스폿 용접되어 연결되어 있고 미세한 많은 구멍을 갖고있는 적층형 충진발열테로 특수하게 설계된 유도 가열기는 외부에 워크 코일로 감겨져 있는 불소수지계의 절연용기 안에 삽입되어 있다. 이 워크 코일은 공진형 인버터와 연결되어 있으며 유도가열기를 통해 흐르는 관 유체를 1단가열부에서 저압의 포화증기를 2단가열부에서 열방사성 증발유체를 생성하는 본 DPH시스템의 성능 및 효용성을 실용적인 측면에서 논의하고 평가 할 것이다.

• Nuclear Engineering and Technology
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• 제56권6호
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• pp.2395-2403
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• 2024

With the rapid development of DC high voltage accelerator, higher requirements have been raised for the design of DC high voltage power supply, requiring more stable high voltage with lower output ripple. Therefore, it also puts forward higher requirements for the parameter design of the voltage doubling rectifier circuit, which is the core component of the DC high voltage power supply. In order to obtain output voltage with better performance, the effects of the working frequency, the stage capacitance and the load resistance on the output voltage of the voltage doubling rectifier circuit are studied in detail by simulation. It can be concluded that the higher the working frequency of the transformer, the larger the stage capacitance, the larger the load resistance and the better the output voltage performance in a certain range. Based on this, a 2.5 MV voltage doubling rectifier circuit driven by a 120 kHz frequency transformer is designed, developed and tested for the power supply of the neutron source device towards BNCT. Experimental results show that this voltage doubling rectifier circuit can satisfy the design requirements, laying a certain foundation for the engineering design of DC high voltage power supply of neutron source device.

• 한국학교ㆍ지역보건교육학회지
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• 제17권1호
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• pp.59-73
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• 2016

Objectives: The working environment affects employees' physical and mental aspects, and has a deep associations with depression. The purposes of this study are to investigate how hazardous environment working experience impacts on depression, to provide rationale and practical implications for reducing depression and drinking. Methods: This study targeted 215 dental hygiene students from 3 universities located in Gyeonggi-do from November 30 to December 4, 2015. We analyzed the data with frequency analysis, descriptive statistics, t-test. One-way ANOVA, Pearson correlation coefficient, Regression analysis by using SPSS. Results: This study showed that experience working in hazardous environments increased depression and alcohol drinking, on the other hand alcohol drinking reduced depression. In addition, experience working in hazardous environments effected on depression indirectly through mediating of drinking, subjective health had not role of Moderating Effects between experience working in hazardous environments and depression. Conclusions: In order to reduce workers' depression and alcohol, the improvements of harmful environment are needed. For this governments and local governments should efforts to support enhancing workplace environment, to develop model of standard work environment, and to change employers' awareness on the harmful environment.

• 대한치과기공학회지
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• 제33권4호
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• pp.517-528
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• 2011

Purpose: In this study, we aim to provide fundamental database for the development of programs that will enhance the satisfactions of the dental technicians' daily life. To this end, we examined various factors that affect the subjects' social and emotional life satisfactions and their overall daily lives. Methods: Out of the random selection of the registered dental offices of Dental Technicians in Seoul, Gyeonggido, and Gangwon-do districts. Four hundred working dental technicians were asked to fill out the questionnaire from the 1st of June to the 25th of August, 2011. We collected the 355 sheets of the questionnaire and took frequency analysis, t-test, analysis of variance and structural equation modeling using SPSS Win 12.0 program. Results: The results of this study is as follows; Firstly, social satisfaction of the subjects turned out 3.71 on average, emotional satisfaction and daily life satisfaction in general were shown 2.77 and 3.19 respectively. Secondly, Age(p<.05), Career(p<.001), Working environment satisfaction(p<.001) showed significant differences in social life satisfaction area, whereas monthly earning(p<.05), working environment satisfaction(p<.001) revealed meaningful differences in the domain of emotional life satisfaction. Thirdly, in the overall satisfaction of daily lives, monthly earning(p<.05), career(p<.01), working environment satisfaction(p<.001) indicated significant difference. Conclusion: Seen from the results of this study, we purport to develop a variety of programs for better working conditions and to further research on the variables affecting the dental technicians' satisfaction of daily lives.

• 한국초전도ㆍ저온공학회논문지
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• 제14권3호
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• pp.48-52
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• 2012

This paper describes experimental study on the orientation dependence of GM-type pulse tube refrigerator with helium and neon as working gas. A pulse tube refrigerator generates refrigeration work with gas expansion by gas displacer in the pulse tube. The pulse tube is only filled with working gas and there exists secondary flow due to large temperature difference between cold-end and warm-end. The stability of secondary flow is affected by orientation of cold-head and thus cooling performance is deteriorated by gas mixing due to secondary flow. In this study, a single stage GM-type pulse tube with orifice valve as a phase control device is fabricated and tested. The fabricated pulse tube refrigerator is tested with two different working gases of helium and neon. First, optimal valve opening and operating frequency are determined with experimental results of no-load test. And then, the variation of no-load temperature as orientation angle of cold-head is measured for two different working gases. Effect of orientation dependence of cold-head as working gas is discussed with experimental results.

• 대한치위생과학회지
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• 제5권2호
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• pp.1-11
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• 2022

Background: This study was aimed at investigating the type of work of dental hygienists and identifying factors affecting the subjective health status according to hazardous risk factors in the working environment. Methods: From May 15 to 31, 2019, we surveyed 411 dental hygienists working at dental hospitals in the metropolitan area. SPSS 25.0 was used to perform the frequency analysis, t-test, one-way analysis of variance, Pearson's correlation analysis, and multiple regression analysis. Results: Regarding factors related to the degree of exposure to hazardous risk factors in the work environment and subjective health status, the more exposed the ergonomic (p<0.05) and psychological (p< 0.001)factors, the worse is the subjective health status. Conclusion: The results of this study suggest that the working environment should be improved for dental hygienists such that they can perform their duties in a safe environment.

• 한국건설관리학회논문집
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• 제24권6호
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• pp.81-90
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• 2023

Climate change has resulted in increased frequency and intensity of heat waves, which poses a significant threat to the health and safety of construction workers, particularly those engaged in labor-intensive and heat-stress vulnerable working environments. To address this challenge, this study aimed to propose an interpretable machine learning approach for forecasting personal heat strain by considering the cumulative effect of heat exposure as a situational variable, which has not been taken into account in the existing approach. As a result, the proposed model, which incorporated the cumulative working time along with environmental and personal variables, was found to have superior forecast performance and explanatory power. Specifically, the proposed Multi-Layer Perceptron (MLP) model achieved a Mean Absolute Error (MAE) of 0.034 (℃) and an R-squared of 99.3% (0.933). Feature importance analysis revealed that the cumulative working time, as a situational variable, had the most significant impact on personal heat strain. These findings highlight the importance of systematic management of personal heat strain at construction sites by comprehensively considering the cumulative working time as a situational variable as well as environmental and personal variables. This study provided a valuable contribution to the construction industry by offering a reliable and accurate heat strain forecasting model, enhancing the health and safety of construction workers.

• 여성건강간호학회지
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• 제30권1호
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• pp.67-78
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• 2024

Purpose: The present study investigated experiences of traumatic perinatal events, the provision of related education, and educational needs of nurses working in the labor and delivery room (LDR). Methods: Nurses working in the LDRs of six institutions and two nurse portal sites were invited to participate in the survey, delivered on paper or online. The data were collected from October 1 to November 25, 2022. Data from 129 nurses were analyzed using frequency, the chi-square test, the Fisher exact test, the t-test, and analysis of variance. Results: Virtually all participants (98.6%) reported having experienced at least one traumatic perinatal event (dystocia, postpartum hemorrhage, neonatal congenital anomalies, severe maternal or neonatal injury, stillbirth, and maternal or neonatal death) while working in the LDR. The most shocking traumatic perinatal event experienced was the maternal or neonatal death (40.3%), but 24.8% of participants did not recall ever receiving education on the topic. About 63% of participants experienced traumatic perinatal events within a year of working in the LDR. The average score for education needs regarding traumatic perinatal events was 3.67±0.37 out of 4, and participants preferred simulation education as the most effective educational method. Conclusion: Since most of the participants had experienced various traumatic perinatal events in the early stages of working in the LDR and expressed a high level of need for education on traumatic perinatal events, it is necessary to provide more effective stimulation education programs in the early period of work in the LDR.

• Journal of Power Electronics
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• 제11권1호
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• pp.28-36
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• 2011

In this paper, a three phase cycloconverter type high frequency AC link inverter is discussed. The configuration consists of a high frequency full-bridge inverter and a high frequency transformer followed by a three phase cycloconverter whose switch is composed of anti-series connected MOSFETs with a common source. A simple digital control strategy based on space vector modulation (SVM) and repetitive control for the cycloconverter is proposed although its input voltage is a high frequency AC pulse. The operation principle of the proposed control strategy is analyzed and the equivalent working modes during one interval are also presented. The effectiveness of the proposed control strategy is verified through Matlab/Simulink simulations and experiments on a 1.45kW prototype.