• Journal of Dental Anesthesia and Pain Medicine
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• v.17 no.4
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• pp.289-295
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• 2017

Background: This study is aimed to evaluate the level of fear and to reduce the overall fear, thereby enabling patients to receive treatment via timely visits. Methods: In a survey conducted by 460 South Korean middle school students, we used 453 data that faithfully responded to the survey. Multiple regression analysis was conducted to investigate the factors influencing subjective oral health and dental fear. The significance level used for statistical significance was ${\alpha}=0.05$. Results: The level of fear was higher for upper grade, female students. The factors affecting dental fear were higher for gingival bleeding and dental pain. Regarding factors for dental fear affecting subjective oral health, lower fear of puncture needle and tooth removal tool resulted in higher subjective oral health. Conclusions: The study found that adolescents had higher fear of dental care when they had gingival bleeding and tooth pain. Gingival bleeding is a symptom of early gingival disease and dental pain is likely due to advanced dental caries. These results suggested that it is necessary to have a program to reduce dental fear and anxiety as well as a program to prevent dental diseases through regular periodic screening and education.

• Korean Journal of Veterinary Research
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• v.61 no.3
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• pp.25.1-25.7
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• 2021

The axolotl has extraordinary regeneration capacity compared to other vertebrates. This remarkable potential has been attributed to its life-long neoteny, characterized by the exhibition of embryonic characteristics at the adult stage. A recent study provided a detailed morphological analysis of the sperm morphology of the Ambystoma mexicanum using routine and detailed histological techniques. The primary purpose of the present study is to describe a simple and inexpensive method for evaluating the morphology of axolotl sperm. In this study, spermatophore structures were collected and spread on slides and air-dried. The slides were stained with periodic acid Schiff, toluidine blue, Masson's trichrome, Giemsa, Spermac, and Diff-Quik dye for a morphological examination. The slides were coated with gold/palladium for a scanning electron microscopy examination. The sperm of the axolotl consisted of an elongated head, a neck, and a flagellum covered with an undulating membrane. The lengths of the midpiece, tail, and head were 8.575 ㎛, 356.544 ㎛, and 103.661 ㎛, respectively. In the flagellum part, the wavy membrane structure, whose function has not been explained, surrounds the tail. The data obtained from this study will constitute an important step in designing future research on the reproductive and regeneration capacity of the axolotl.

• Progress in Superconductivity and Cryogenics
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• v.23 no.1
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• pp.7-11
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• 2021

Cryogenic vessels are special equipment that requires periodic evaluation of their thermal insulation performance. At the current standard, the test is considered as the loss product or heat leakage of cryogenic vessel, which takes over 72 h to evaluate; consequently, a large amount of working medium is discharged to the environment in the process. However, hydrogen is flammable and explosive, and the discharged gas may be dangerous. If liquid hydrogen is replaced with liquid nitrogen before testing, the operation then becomes complicated, and the loss product or heat leakage cannot respond to the thermal insulation performance of cryogenic vessels for liquid hydrogen. Therefore, a novel method is proposed to evaluate the heat leakage of cryogenic vessels for liquid hydrogen in self-pressurization. In contrast to the current testing methods, the method proposed in this study does not require discharge or exchange of working medium in all test processes. The proposed method is based on one-dimensional heat transfer analysis of cryogenic vessels, which is verified by experiment. When this method is used to predict the heat leakage, the comparison with the experimental data of the standard method shows that the maximum error of heat leakage is less than 5.0%.

• Journal of Sensor Science and Technology
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• v.28 no.1
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• pp.36-40
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• 2019

Energy harvesting is an advantageous technology for wireless sensor networks (WSNs) that dispenses with the need for periodic replacement of batteries. WSNs are composed of numerous sensors for the collection of data and communication; hence, they are important in the Internet of Things (IoT). However, due to low power generation and energy conversion efficiency, harvesting technologies have so far been utilized in limited applications. In this study, a piezoelectric energy harvester was modeled in a vibration environment. This harvester has an oval-shaped configuration as compared to the conventional cantilever-type piezoelectric energy harvester. An analytical model based on an equivalent circuit was developed to appraise the advantages of the oval-shaped piezoelectric energy harvester in which several structural parameters were optimized for higher output performance in given vibration environments. As a result, an oval-shaped energy harvester with an average output power of 2.58 mW at 0.5 g and 60 Hz vibration conditions was developed. These technical approaches provided an opportunity to appreciate the significance of autonomous sensor networks.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.25 no.4
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• pp.293-300
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• 2018

Purpose: This study was done to identify the relationship between nurses' compliance with safety guidelines for the use of antineoplastic agents, observable symptoms, and stress from occupational exposure. Methods: The participants were 172 nurses from six general hospitals in a metropolitan area. They had administered antineoplastic agents at least three months prior to the study. Data were collected using self-report questionnaires, and then analyzed using SPSS/WIN 23.0 for descriptive statistics, t-test, one-way ANOVA, $Scheff\acute{e}$ method, and Pearson correlation coefficient. Results: The average score on the guideline for safety compliance was 87.75 points out of a total of 100. The average score for observable symptoms of exposure to antineoplastic agents was 30.12 (28~56) points, and that for mean stress was 33.52 (15~60) points. Observable symptoms and stress from occupational exposure showed a statistically significant positive correlation (r=0.34, p<.001). Conclusion: To increase the degree of compliance with safety guidelines for antineoplastic agents, hospitals should lower the chance of exposure to antineoplastic agents, as well as minimize the observable symptoms and stress from occupational exposure. Periodic education and policy support are needed to improve compliance with safety guidelines for antineoplastic agent use.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.5
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• pp.313-319
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• 2021

The national geodetic reference frame of Korea was adopted in 2003, which is referenced to ITRF (International Terrestrial Reference Frame) 2000 at the epoch of January 1, 2002. For precise positioning based on the satellites, it should be thoroughly maintained to the newest global reference frame. Other than plate tectonic motion, there are significant events or changes such as earthquakes, antenna replacement, PSD (Post-Seismic Deformation), seasonal variation etc. We processed three years of GNSS (Global Navigation Satellite System) data(60 NGII CORS stations, 51 IGS core stations) to produce daily solutions minimally constrained to ITRF. From the time series of daily solutions, the sites with unexpected discontinuity were identified to set up an event(mostly antenna replacement). The combined solution with minimum constraints was estimated along with the velocity, the offsets, and the periodic signals. The residuals show that the surrounding environment also affects the time series to a certain degree, thus it should be improved eventually. The transformation parameters to ITRF2014 were calculated with stability and consistency, which means the national geodetic reference frame is properly aligned to the global reference frame.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.134-142
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• 2021

This paper proposes a probabilistic method in analyzing timing measurements to determine the periodicity of real-time tasks. The proposed method fills a gap in existing techniques, which either concentrate on the estimation of worst-case execution times, or do not consider the stochastic behavior of the real-time scheduler. Our method is based on the Z-test statistical analysis which calculates the probability of the measured period to fall within a user-defined standard deviation limit. The distribution of the measured period should satisfy two conditions: its center (statistical mean) should be equal to the scheduled period of the real-time task, and that it should be symmetrical with most of the samples focused on the center. To ensure that these requirements are met, a data adjustment process, which omits any outliers in the expense of accuracy, is presented. Then, the Z-score of the distribution according to the user-defined deviation limit provides a probability which determines the periodicity of the real-time task. Experiments are conducted to analyze the timing measurements of real-time tasks based on real-time Linux extensions of Xenomai and RT-Preempt. The results indicate that the proposed method is able to provide easier interpretation of the periodicity of real-time tasks which are valuable especially in comparing the performance of various real-time systems.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.1
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• pp.114-130
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• 2021

With the drastic growth of Information and Communication Technology (ICT) industry, global energy consumption is exponentially increased by mobile communications. The huge energy consumption and increased environmental awareness have triggered great interests on the research of dynamic distribution of cell user and traffic, and then designing the energy efficient cellular network. In this paper, we explore the temporal and spatial characteristics of human mobility and traffic distribution using real data set. The analysis results of cell traffic illustrate the tidal effect in temporal and spatial dimensions and obvious periodic characteristics which can be used to design Base Station (BS) dynamic with sleeping or shut-down strategy. At the same time, we designed a new Cell Zooming and BS cooperation mode. Through simulation experiments, we found that running in this mode can save about 35% of energy consumption and guarantee the required quality of service.

• Journal of muscle and joint health
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• v.28 no.2
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• pp.102-110
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• 2021

Purpose: This study aimed to verify the effects of a community-based fall prevention exercise program for older adults on lower extremity muscle strength, balance ability, and fall efficacy. Methods: This study recruited 30 participants, and the program was conducted for 10 weeks. The program included sessions on strength and balance exercises, conducted for 50 minutes a day and at least three times a week. The collected data were analyzed using non-parametric (Wilcoxon signed-rank test, generalized estimated equation) and parametric statistics (paired t-test, rmANOVA). Results: After 12 weeks of exercise program, lower extremity muscle strength and static-dynamic balance ability significantly increased. The fall efficacy increased from an average score of 2.48 points before the test to an average score of 2.91 points after the test. Regarding general characteristics, there were no significant differences in effect before and after the program, except for fall efficacy. Conclusion: The above results showed that the intervention of a community-based fall prevention exercise program for older adults was effective. Therefore, it is suggested that this exercise program be organized regularly within the center to provide periodic and long-term services.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.1
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• pp.3-12
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• 2001

In this paper, a synchronized stream encryption system for secure link layer communication in a radio channel is designed. Interleaving scheme which is used to enhance the transmission performance over a fading channel is applied to the encrypted information. A designed synchronous scream cipher system consists of a keystream generator, a synchronization pattern generator and a session key generator. The structure of a synchronous stream cipher system with periodic synchronization is composed of the encrypted information which consists of a synchronization pattern, an error correcting coded session key, an encrypted data in a period of synchronization. In this paper, interleaving scheme using dynamic allocation a1gorithm(DAA) is applied the encrypted information. The BER of the DAA has been slightly higher than that of the SAA(static allocation algorithm).