• The Journal of the Acoustical Society of Korea
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• v.42 no.3
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• pp.243-249
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• 2023

The occurrence of cavitation on the propeller is directly linked to the naval ship's survivability, and it is necessary to design a propeller shape that delays the cavitation inception. However, the propeller cavitation can occur under various operating conditions, thus it is important to identify whether the propeller cavitation exists during operation as well as in the design phase. To this end, it is necessary to use noise or vibration signals on board to monitor the cavitation inception. In this study, a hydrophone and an accelerometer were installed on the ship hull right above the propeller to compare the performance of analyzing cavitation inception between acoustic and vibration signals. Also, a high speed camera was used to visually observe the occurrence of cavitation through an observation window. The measured results showed that the spectral shapes between acoustic and vibration signals were different, but the level increases at each frequency band and the overall level of the frequency band from 1 kHz to 10 kHz showed a similar tendency. The Detection of Envelope Modulation On Noise (DEMON) analysis also showed similar results for both acoustic and vibration signals, confirming that both hydrophones and accelerometers can be utilized in the analysis of cavitation inception.

• Science of Emotion and Sensibility
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• v.25 no.4
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• pp.33-44
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• 2022

Rental services have recently come to be provided in which people can experience traditional Korean culture in the form of Hanok villages, allowing everyone can easily rent and wear hanbok, a traditional Korean garment, regardless of gender and age. Users of hanbok rental services share photos of themselves wearing hanbok on social media, contributing to the increasing popularity of hanbok experiences. However, the trend of wearing hanbok has no become established in people's daily lives, apart from the specific places that offer hanbok experiences. To promote hanbok as everyday clothes, hanbok design should be developed to provide wearers with both convenience and emotional satisfaction. Using 28 emotion words that express consumers' emotions toward hanbok that were extracted from previous studies, this study measured consumers' emotions toward different types of hanbok with on a seven-point Likert scale. Emotion words and categories that obtained scores of five points or above, signifying a rating of "felt fairly" or higher in relation to specific hanbok types were extracted. This study also examined differences in the average scores for emotional categories according to hanbok types and gender. The results indicated that only average scores for the "favorable feeling" category showed a significant difference between men and women. Finally, differences in the average scores for emotional categories were examined by classifying hanbok types: traditional (e.g., baenaet-jeogori, saekdong-jeogori, traditional hanbok for adults, and traditional wedding clothes) and modern (e.g., daily hanbok for children, for women, and for men). The results indicated significant differences between traditional and modern hanbok in six emotional categories (i.e., the cheerful, esthetic, harmonious, fresh, favorable, and stable feeling). This study derived analytic results for terms related to emotions that hanbok wearers feel according to types of hanbok. The findings can be used by hanbok retailers and rental services to provide consumers with greater emotional satisfaction.

• 한국체육학회지인문사회과학편
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• v.54 no.3
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• pp.31-43
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• 2015

The purpose of this study was to find out the dance sports athlete's factor that presents performance problems and performance enhancing for competitions. To achieve purpose of study carried out open-ended question and structural inquiry of succession in the dance sports athlete of 25 people, the open-ended questions data were examined through inductive content analysis procedure, conducted preliminary investigation to 100 people. Preliminary investigation and main survey were verified to the dance sports athlete of 137 people through exploratory factor analysis, and confirmatory factor analysis was conducted. On the basis of the results, the conclusions were drawn as follows; First, hinders factors to athletic performance is discord with partner, condition, contest environment, limit of physical strength, limit of economic strength. Second, the measurement scale of dance sports athlete's performance enhancing to competition with 23 items which are consisted of 7 main factors. The determination factors of dance sports athlete performance were partnership, ability to invest, spiritual factors, training factors, ability of physical factors, the leader, environment of competition.

• 한국체육학회지인문사회과학편
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• v.57 no.1
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• pp.405-419
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• 2018

This study of the Wholeness Program relevant to dementia behavior and verification of buffering effects. For the purpose of this, among those who were attending Day Care Centers belonging to Seniors Welfare Center of M1 and M2 located in Seoul. Among those who met all these requirements, 40 senior citizens were finally selected. After carrying out a preliminary test to the selected subjects, 20 elderly of Seniors Welfare Center of M1 were randomly placed as an experimental group, while other 20 people of Seniors Welfare Center of M2, as a control group. The Wholeness Program relevant to dementia behavior was carried out from March 14 to May 30 of 2016, for 12 weeks, twice a week. As for the measurement tool, this study depended on the Korean version of Mini Mental State Examination (MMSE-K), the Korean version of Modified Barthel Index (K-MBI) and the Korean version of Geriatric Depression Scale (GDS-K). While the elderly were participating in the Wholeness Program relevant to dementia behavior, they were measured two times in total, before and after the participation in dementia behavior. Based on SPSS-PC (version 21.0), firstly, independent t-test was carried out to understand the homogeneity between the experimental group and the control group. Secondly, matched-pair t-test was carried out between preliminary test and post-test to inquire into the effects of MMSE-K, K-MBI and GDS-K. Thirdly, ANOVA was conducted to confirm the variation (change amount) between preliminary test and post-test. According to the survey results, the Wholeness Program relevant to dementia behavior of the elderly shows overall effects in all spheres of changes of cognitive ability (MMSE-K), changes of physical capacity (K-MBI) and changes of depression level (GDS-K).

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.1
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• pp.64-77
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• 2022

Objectives: The purpose of this study is to objectify the level of case management performance and the factors influencing performance, to improve the case management performance at the Korea Worker's Compensation & Welfare Service (KWCWS) on the basis of the recognition of the objective realities of case management by job coordinators at the KWCWS, to develop a model of case management fit for the KWCWS, and to provide a basis for establishing guidelines for standardized case management. Methods: A total of 156 questionnaires were distributed to job coordinators at the KWCWS's headquarters, six regional headquarters, and 55 branches. One hundred forty-one questionnaires were collected and 126 were analyzed statistically using SPSS 21.0. Factor analysis and reliability analysis were conducted to verify the validity and reliability of the main measurement items in the research model. Frequency analysis was conducted for general characteristics of survey subjects. Frequency analysis or descriptive statistics were conducted to identify the level of independent variables (case manager's individual variables, job variables, institutional and organizational variables). Dependent variables (case management performance) and the degree of correlation were analyzed through correlation analysis between research variables. Multiple regression analysis and hierarchical regression analysis were conducted to examine the effect of independent variables on case management performance. Results: The results of the study showed that the level of overall performance in the five stages of case management was ordinary, with an average level of 3.45 on a 5-point scale. Levels of performance by step were institutional approach and intake (3.69), assessment (3.63), goal setting and intervention planning (3.46), implementation of intervention plan (3.32), and evaluation and termination (3.20), in that order. The explanatory power of case management performance (overall) by case managers with the KWCWS was case manager's institutional and organizational variables, job variables, and individual variables, in that order. At each stage of case management, the explanatory power of a case manager's institutional and organizational variables was found to be the greatest. The model changes at each stage of case management assume similar aspects statistically. In hierarchical regression analysis, it was institutional support that had a significant effect on case management performance (overall), and institutional support had the greatest effect. The results of multiple regression analysis in which all variables are input simultaneously showed that institutional support and expertise as well as self-efficacy had a positive effect. However, case management work experience, expertise (technology), and autonomy were found to have a negative effect during the stage of case management performance. Conclusions: As a result of the study, it was confirmed that raising the case manager's expertise and support from the institution and organization are important factors to improve the level of case management performance. The research also derived practical ways of reinforcement of case manager capacity, institutional and organizational support, operation of rehabilitation-case management teams, and occupational health-related aspects.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.3
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• pp.198-203
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• 2023

Purpose. The aim of this study was to evaluate the proximal contact with a dental floss compared to a celluloid strip and a metal strip in normal dental arch and investigate what the most effective method for measuring is. Materials and methods. The subjects of this study was consisted with 20 healthy adults (10 males and 10 females) who had normal dentition. A dentist with more than 5 years of clinical experience evaluated the proximal contacts using a dental floss method, a celluloid strip method, and a metal strip method. Statistical analysis were performed by the use of Mann-Whitney U test. A P-value < .05 was considered statistically significant in all analysis. In addition, in the evaluation of proximal contact using a dental floss, the measurement of proximal contact using a celluloid strip and a metal strip was compared. Results. 80 % of all proximal contact was proper. Proper proximal contact was observed at the posterior area compared to the anterior area (P < .05). And male had proper proximal contact at the anterior area, female had proper proximal contact at the posterior area (P < .05). The consistency analysis between the results of the celluloid strip and the metal strip experiment on the results obtained from the floss using the consistency scale Kappa index shows that using celluloid strip is more advantageous than using the metal strip. Conclusion. Only 80% of all proximal contact was proper. Using celluloid strips with various thickness for evaluating of proximal contact is considered to be helpful for accurate measuring of proximal contact.

• 한국노년학
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• v.29 no.1
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• pp.117-134
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• 2009

The purpose of this study was designed to develop an questionnaire for healthy aging. The subjects of this study were total 335 people who participated in regular exercise and went to welfare centers in Seoul. The validity and reliability were tested for verifying the developed questionnaire for healthy aging. The data were collected between June 12, 2006 and October 27, 2006. The mean, standard deviation, kurtosis, skewness, reliability, exploratory factor analysis and confirmatory factor were analyzed for statistical purpose using by SPSS-Win 12.0 program. The results were as follows; First, to obtain content validity, the results of previous research and the value system responses were submitted to a judgement group. Second, the results of the factor analysis of the 20 items making up the questionnaire were classified into the following 3 factors; physiological health(6 items), cognitive-mental health(6 items), social-support health(8 items). Third, the reliability of the questionnaire for healthy aging was 0.891(Cronbach's alpha). In the factor analysis Cronbach's alpha correlations for the 4 factors ranged from 0.642 to 0.885. Fourth, the results of confirmatory factor analysis, all the index values(NFI, RFI, CFI, Delta 2 IFI) were close to 1. Thus, this questionnaire demonstrated good reliability and validity and therefore it was an appropriate measurement of healthy aging.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.4
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• pp.199-208
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• 2023

Taguchi method is one of the most popular approaches for design optimization such that performance characteristics become robust to uncontrollable noise variables. However, most previous Taguchi method applications have addressed a single-characteristic problem. Problems with multiple characteristics are more common in practice. The multi-criteria decision making(MCDM) problem is to select the optimal one among multiple alternatives by integrating a number of criteria that may conflict with each other. Representative MCDM methods include TOPSIS(Technique for Order of Preference by Similarity to Ideal Solution), GRA(Grey Relational Analysis), PCA(Principal Component Analysis), fuzzy logic system, and so on. Therefore, numerous approaches have been conducted to deal with the multi-characteristic design problem by combining original Taguchi method and MCDM methods. In the MCDM problem, multiple criteria generally have different measurement units, which means that there may be a large difference in the physical value of the criteria and ultimately makes it difficult to integrate the measurements for the criteria. Therefore, the normalization technique is usually utilized to convert different units of criteria into one identical unit. There are four normalization techniques commonly used in MCDM problems, including vector normalization, linear scale transformation(max-min, max, or sum). However, the normalization techniques have several shortcomings and do not adequately incorporate the practical matters. For example, if certain alternative has maximum value of data for certain criterion, this alternative is considered as the solution in original process. However, if the maximum value of data does not satisfy the required degree of fulfillment of designer or customer, the alternative may not be considered as the solution. To solve this problem, this paper employs the desirability function that has been proposed in our previous research. The desirability function uses upper limit and lower limit in normalization process. The threshold points for establishing upper or lower limits let us know what degree of fulfillment of designer or customer is. This paper proposes a new design optimization technique for multi-characteristic design problem by integrating the Taguchi method and our desirability functions. Finally, the proposed technique is able to obtain the optimal solution that is robust to multi-characteristic performances.

• Journal of Korean Society of Disaster and Security
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• v.16 no.2
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• pp.85-98
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• 2023

Flood is one of the most frequent natural disasters worldwide. In Korea, the probability of urban flooding is greatly increasing due to complex factors such as global warming, an increase in impervious areas, and limitations in expanding water supply facilities in existing urban areas. However, large-scale civil engineering works to prevent urban inundation are socially and economically difficult to obtain national consent. Recently the importance of resilience, which is the ability to return to the original state after a disaster through rapid recovery while preparing for natural disasters to a level that the local community can afford socially and economically, is increasing. Accordingly, various studies on urban resilience have been conducted, but the resilience measurement method related to the lifeline that provides essential services of the city is insufficient. However, among lifelines, road networks are important facilities for the transportation of recovery resources and rapid recovery in the event of a natural disaster, so road networks are a major factor that must be considered when measuring the degree of recovery of a city in the field of natural disasters. Therefore, this study proposes a recovery evaluation method considering the characteristics of resilience and road networks in the urban flooding field and analyzes the effect of road networks on urban resilience.

• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.1009-1015
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• 2023

This study was a one-group pretest-posttest design experimental study that attempted to verify the effects of applying the Havruta learning method on the academic self-efficacy, academic achievement, and communication skills of radiology college students. This study was conducted from May 1 to June 23, 2023, and applied the Havruta learning method for 6 weeks to 38 second-year radiologists taking a radiology technology course at a university in Jeollanam-do. SPSS/WIN 21.0 was used for data analysis, the reliability of the scale was verified, the subject's general characteristics, pre-test values and post-test values for measurement variables were verified with descriptive statistics, and the difference between before and after the Havruta learning method was verified with paired t-test. Research results show that the Havruta learning method improves academic self-efficacy (t=-2.70, p<.001), academic achievement (t=-2.87, p=.006), and communication skills (t=-2.76, p=.008). showed a statistically significant difference. As a result, Havruta learning method was confirmed as an effective learning method that improves academic self-efficacy, academic achievement, and communication skills of radiology college students. In the future, expanded application of the Havruta learning method will be necessary.