• Nuclear Engineering and Technology
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• 제53권12호
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• pp.4080-4092
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• 2021

In this study, the performance of sequence tracking methods for multiple interaction events in specific CdZnTe Compton imagers was evaluated using Monte Carlo simulations. The Compton imager consisted of a 6 × 6 array of virtual Frisch-grid CZT crystals, where the dimensions of each crystal were 5 × 5 × 12 mm³. The sequence tracking methods for another Compton imager that consists of two identical CZT crystals arrays were also evaluated. When 662 keV radiation was incident on the detectors, the percentages of the correct sequences determined by the simple comparison and deterministic methods for two sequential interactions were identical (~80%), while those evaluated using the minimum squared difference method (55-59%) and Three Compton method (45-55%) for three sequential interactions, differed from each other. The reconstructed images of a 662 keV point source detected using single and double arrays were evaluated based on their angular resolution and signal-to-noise ratio, and the results showed that the double arrays outperformed single arrays.

• 한국산업보건학회지
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• 제29권2호
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• pp.217-225
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• 2019

Objectives: The aim of this study is to evaluate the quality management systems of domestic asbestos survey and monitoring service providers and the relationships with the number of licenses or designations and sales performances. Methods: Data on quality management systems were collected by assessors who were assigned by the Korea Occupational Safety and Health Agency(KOSHA) during a pilot evaluation program for designated asbestos survey and monitoring service providers in 2016 using evaluation criteria developed by KOSHA. Basic characteristics, evaluated scores, and sales performance were gathered and statistically analyzed. Results: The median and arithmetic mean of the total scores were 0.64 and 0.66. Evaluation fields that scored highly with the highest percentages were sales performance, installation and availability of equipment, compliance with the mandatory minimum number of airborne samples, laboratory independence, and results of proficiency analytical testing, in that order. Evaluation fields that received low marks with the highest percentages were the training of personnel, blank field samples, calibration of flow rates, preliminary check and visual inspection of the work area prior to the clearance test, and review and approval of final reports, in that order. Comparison of normalized scores between service providers registered for asbestos and other tasks and those designated for only asbestos showed significant differences in their evaluated scores. Sales performance did not show a positive correlation with evaluated scores. Conclusions: The quality management systems of domestic asbestos survey and monitoring service providers were poor. High scores were recorded mostly in evaluation fields related to regulatory requirements. Low scores were recorded mostly in evaluation fields related to documentation and recordkeeping. Considering the low influence of quality on sales performance, the government needs to evaluate the quality management of asbestos survey and monitoring service providers and provide the results to public in order to address their low levels of quality management.

• 식품보건융합연구
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• 제8권1호
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• pp.9-16
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• 2022

Recently, the use of serving robots has been increasing due to the increase in preference for non-face-to-face services and the rise in the minimum wage due to the coronavirus. When analyzing previous studies related to serving robots, it was confirmed that most of the studies on the functions and technologies of serving robots were conducted. Therefore, this study analyzed the factors affecting the attitude and customer satisfaction of restaurant consumers toward serving robots by adding performance expectations, effort expectations, and speed factors among the UTAUT2 models. The survey period was conducted from July 28, 2021 to September 9, 2021, and 306 out of a total of 310 surveys were used for analysis, excluding 4 unfaithful surveys. For the analysis, exploratory factor analysis, reliability analysis, confirmatory factor analysis, and hypothesis test were performed using SPSS 20.0 and AMOS 20.0, and the research results are as follows. First, it was found that performance expectation, effort expectation, and speed had a significant positive (+) effect on attitudes. Second, it was found that attitude had a significant positive (+) effect on customer satisfaction. This study researched customer selection attributes of robot service restaurants using the UTAUT2 model, and also provided academic and practical implications.

• 대한치과기공학회지
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• 제36권4호
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• pp.277-296
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• 2014

Purpose: This study intends to set standard for organizing the curriculum of short-term dental technicians and the change of job environment, as well as the knowledge & training, by identifying the importance and actual job performance of dental technicians following job analysis in the university education of Dept. of Dental Laboratory Technology, and furthermore to foster junior executives to cope with modernization and globalization. Methods: The tools used in this study are based on the job analysis of research report suggested by National Health Personnel Licensing Examination Board(Lee Gyu-seon, 2011), and it consists of general characteristic 7 items. Every competence duty was measured through Likert 5 point gauging, and internal consistency through Cronbach's Alpha. The competence importance of entire questionnaire was .984 and its performance was .874, reflecting considerably high level, and in terms of each competence duty, high credibility was proved and high internal consistency was verified with competence importance ranging from the minimum .655 to the maximum .966 and its performance ranging from the minimum .677 to the maximum .993. Results: Competence importance and its performance in each duty on the job analysis of dental technicians were measured. In competence importance in each duty, the highest was "checking design order form"(average, 4.52), followed by "selling dental prosthesis"(average 4.49), "making removable orthodontic appliance"(average, 4.48), "open managing dental laboratory"(average, 4.46) in order. However, "making complete denture" was found the lowest(average, 4.23), with importance of all competence dutys was considerably high level. In the performance of its competence duty, "checking design order form"(average, 4.04) was found to be the most importance competence, followed by "making conservative restoration"(average, 4.00), "making porcelain"(average 3.98), "checking working cast"(average, 3.90) in order. However it was found out that "making fixed orthodontic appliance"(average, 3.12) was the lowest, and the importance of all competence dutys was quite high level. Conclusion: The duties of dental technicians consist of 13 kinds, in total, and it was found out that "checking design order form"(average, 4.52) was the most important in the competence importance and job performance. In particular, it was revealed that there was a great difference between the competence importance and its performance in the order of "selling dental prosthesis", "open managing dental laboratory", "making removable orthodontic appliance", "making CAD/CAM prosthesis", and then "making fixed orthodontic appliance".

• 한국인공지능학회지
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• 제12권2호
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• pp.1-7
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• 2024

In this paper, we compare three models (logistic regression, Random Forest, and XGBoost) for predicting stroke occurrence using data from the Korea National Health and Nutrition Examination Survey (KNHANES). We evaluated these models using various metrics, focusing mainly on recall and F1 score to assess their performance. Initially, the logistic regression model showed a satisfactory recall score among the three models; however, it was excluded from further consideration because it did not meet the F1 score threshold, which was set at a minimum of 0.5. The F1 score is crucial as it considers both precision and recall, providing a balanced measure of a model's accuracy. Among the models that met the criteria, XGBoost showed the highest recall rate and showed excellent performance in stroke prediction. In particular, XGBoost shows strong performance not only in recall, but also in F1 score and AUC, so it should be considered the optimal algorithm for predicting stroke occurrence. This study determines that the performance of XGBoost is optimal in the field of stroke prediction.

• 한국멀티미디어학회논문지
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• 제10권12호
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• pp.1741-1751
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• 2007

The imprecise computation technique ensures that all time-critical tasks produce their results before their deadlines by trading off the quality of the results for the computation time requirements of the tasks. In the imprecise computation, most scheduling problems of satisfying both 0/1 constraints and timing constraints, while the total error is minimized, are NP-complete when the optional tasks have arbitrary processing times. In the previous studies, the reasonable strategies of scheduling tasks with the 0/1 constraints on uniprocessors and multiprocessors for minimizing the total error are proposed. But, these algorithms are all off-line algorithms. Then, in the on-line scheduling, NORA(No Off-line tasks and on-line tasks Ready upon Arrival) algorithm can find a schedule with the minimum total error. In NORA algorithm, EDF(Earliest Deadline First) strategy is adopted in the scheduling of optional tasks. On the other hand, for the task system with 0/1 constraints, NORA algorithm may not suitable any more for minimizing total error of the imprecise tasks. Therefore, in this paper, an on-line algorithm is proposed to minimize total error for the imprecise real-time task system with 0/1 constraints. This algorithm is suitable for the imprecise on-line system with 0/1 constraints. Next, to evaluate performance of this algorithm, a series of experiments are done. As a consequence of the performance comparison, it has been concluded that IOSMTE(Imprecise On-line Scheduling to Minimize Total Error) algorithm proposed in this paper outperforms LOF(Longest Optional First) strategy and SOF(Shortest Optional First) strategy for the most cases.

• 대한방사선기술학회지:방사선기술과학
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• 제15권1호
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• pp.79-87
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• 1992

It is a matter of common knowledge that madical radiation is most accented for of radiation is doses applied to the whole of people, and of them the radation dose by radiography diagnosis is mainly prevalent. In applying X-rays to a certain man for radiography diagnosis a radiologyist will have to have an absolute sense of mission concerning the reduction and prevention of the patient's radiation dose as the radiologyist obligation. Accordingly, the radiography conditions of the patient's chest employed 197 medical facilites were surveyed and skin dose was computated by the IPH Bit system and examined. As a result, it was shown that the average skin dose was $288\;{\mu}Sv$, its minimum value was $1600\;{\mu}Sv$, which was over 32 times its minimum value. This shows that the appropriate radiography method has not been applied at applying X-ray to the patient. It comes from the performance of X-ray equipment, the choice of auxiliary equipment materials etc. But the most important thing is to master the appropriate radiography condition, and therefore this point will have to be kept in mind.

• 한국유기농업학회지
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• 제21권4호
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• pp.569-588
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• 2013

The organic foods is the terminology calling the organic products, the organic livestock and the organic processing food. The value of organic food may be evaluated as the index of the nutrient content, the safety and the health promotion. The reason why consumers prefer the organic food in the market is because the value of health promotion to be obtained through its consumption is expected to be bigger than the expense according to the purchase of organic food. This study has the significance in developing the direct evaluation model like the human biomonitoring method. The hypothesis for this study is summarized, "If the metabolome of metabolic syndrome of decreases, the exposure of substance of health harm decreases, the number of hospital care decreases and the quality of life shall be improved if the organic food is incepted in the long term and the health care is managed well". The consumer's cooperative and the health consumer's cooperative select the experimental group of 100 persons and the comparative group of 100 persons in 5 areas in the whole country at the same time to verify this hypothesis. Its rate of change is compared and analyzed by measuring the blood and urine of each biomarkers such as the exposed agriculture pesticides, the nitrate in the body at intervals of 2 months for 1 year. Also, by letting participants in the experiment record the major activity such as the dietary intake and the exercise, etc., in the questionnaire and the performance evaluation form, the statistical analysis for the correlation of this with the metabolome, etc., is conducted. The time that is called minimum 1 year and a lot of expense are required to implement this model. Accordingly, the cooperative study by composing the consortium of the interdisciplinary and the interagency is desirable.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제2권2호
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• pp.99-108
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• 1998

Results obtained from this research showed that the anaerobic contact process was applicable to pear waste with COD removal efficiencies of up to $95\%$ depending on conditions, provided ammonium and phosphate salts were added as well as other nutrients, present in the commercial fertilizer, Milorganite or in yeast extract. These latter materials were required in minimum concentrations of 5 and 1.5 g/L, respectively, in the feed independent of HRT and volatile solids loading rate, with part of the effect due to the mineral fraction. Digestion was satisfactory over the whole range of volatile solids loading rates and liquid retention time of 30 to 0.5 days tested, although treatment efficiency dropped off noticeably between 1 and 0.5 day liquid retention time because of poorer flocculation and separation of anaerobic bacteria. Settling of anaerobic bacteria including methane producing bacteria was related to settling of mixed liquor suspended solids only at 1 to 5 days liquid retention times, at other liquid retention times anaerobic microorganism settled markedly less efficiently than mixed liquor suspended solids. Further studies are being made to provide information of practical and basic interest. Data on the composition of the active fraction of yeast extract might solve many practical nutrient problems encountered with the anaerobic contact process and improve its economics. Further improvement in the flocculation and settling of anaerobic bacteria as well as other bacteria would improve overall performance and allow the use of shorter liquid retention times with dilute waste. Knowledge about the numbers of methane formers present would allow a degree of understanding and control of the process not presently attainable.

• 한국병원경영학회지
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• 제23권4호
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• pp.53-64
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• 2018

Purposes: The hospitals needs to generate a minimum profit, in order to perform its own role such as providing high-quality medical services. The demand for hospital management is increasing, as the social demands are diversified and the financial transparency is emphasized. The purpose of this study is to compare hospitals management based on Dupont Identity, by various hospital classification. Methodology: This study is based on '2016 Statistics for Hospital Management' provided by the Korea Health Industry Development Institute. The hospitals were classified according to the scope of care, the type of establishment, the location, and the number of beds. We analyzed the general and financial characteristics of over 337 hospitals using the method of Dupont Identity. Findings: Net profit margin (PM) has the biggest impact on return of equity (ROE). By the number of beds, general hospital with 160-299 beds have the highest return on equity (ROE). By location, hospitals in local municipalities have higher return on equity than hospitals in urban municipalities. According to the type of establishment, public hospitals have lower business performance, and although they invest more than private hospitals. Practical Implications: This study can inspire interest and provide understanding in hospital management and financial structure, by analyzing through an intuitive indicator named Dupont identity. It is possible to provide basic data for hospital management methods for each financial elements, in order to increase the profitability of hospitals.