• Journal of Korean Home Economics Education Association
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• v.18 no.2 s.40
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• pp.29-45
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• 2006

This study was to investigate the perception of middle school students on the management of the curriculum $\ulcorner$Technology Home Economics$\lrcorner$ according to the 7th National Curriculum. The subjects were 494 third grade students from middle schools located in Seoul, in order to inquire into their perceptions through the questionnaire. The collected data was analyzed with the descriptive statistics, Pearson Chi-Square, t-test, and one-way ANOVA by SPSS Win ver. 12.0 program. The major findings were as follows: Firstly there were gender differences on the interests for the subject of $\ulcorner$Technology Home Economics$\lrcorner$. The girls who were interested in the subject were much more numerous than the boys, but only in the technology part of it, the boys were more interested than the girls. Secondly the students recognized that the experiment & practice for learning $\ulcorner$Technology Home Economics$\lrcorner$ was important. They, however, recognized that its operation in school was not enough to understand the contents. The higher a student viewed the importance of the experiment & practice on $\ulcorner$Technology Home Economics$\lrcorner$, the higher his perception of its usefulness in real life. Thirdly the highest ranking of its usefulness for the contents of the subject $\ulcorner$Technology Home Economics$\lrcorner$ was identified as 'the Computer and Information Processing' and 'the Nutrients and Diet in Adolescence'. These findings suggest that the importance of the experiment & practice was enhanced and the gender differences on the usefulness of the experiment & practice on the each units were considered in order to increase the degree of the students' interest and usefulness of the $\ulcorner$Technology Home Economics$\lrcorner$

• Journal of Korea Water Resources Association
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• v.30 no.5
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• pp.441-447
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• 1997

Rainfall observation using rain gage network or satellites includes the sampling error depending on the observation methods or plans. For example, the sampling using rain gages is continuous in time but discontinuous in space, which is nothing but the source of the sampling error. The sampling using satellites is the reverse case that continuous in space and discontinuous in time. The sampling error may be quantified by use of the temporal-spatial characteristics of rainfall and the sampling design. One of recent works on this problem was done by North and Nakamoto (1989), who derived a formulation for estimating the sampling error based on the temporal-spatial rainfall spectrum and the design scheme. The formula enables us to design an optimal rain gage network or a satellite operation plan providing the statistical characteristics of rainfall. In this paper the formula is reviewed and applied for the sampling error problems using several multi-dimensional precipitation models. The results show the limitation of the formulation, which cannot distinguish the model difference in case the model parameters can reproduce similar second order statistics of rainfall. The limitation can be improved by developing a new way to consider the higher order statistics, and eventually the probability density function (PDF) of rainfall.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.5
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• pp.353-366
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• 2019

This research proposes an optimal flushing operation technique in an effort to prevent secondary water pollutions and accidents in aged pipes, and to improve the cleaning effect of unidirectional flushing. Water flow directions were analyzed using EPANET 2.0, while flushing and air scouring experiments in forward and reverse directions were performed in the field. In 42 experiments, average residual chlorine concentration and turbidity were improved after cleaning compared to before cleaning. It was found that even when the same cleaning method was used, further improvement of cleaning effect was possible by applying air injection and reverse direction cleaning techniques. By means of one-way ANOVA(Analysis of variance), it was also possible to statistically verify the need of actively utilizing air injection and reverse direction cleaning. Based on correlation between turbidity and TSS, the total amount of suspended solids removal was estimated for 874 flushing operations and 194 air scouring operations. The result showed that air scouring used more discharge water than flushing by an average of $4.9m^3$ yet with larger amounts of suspended solids removal by an average of 145.9 g. The result of analysis on turbidity values from 887 flushing operations showed low cleaning effect of unidirectional flushing for the pipes with diameters over 300 mm. In addition, the turbidity values measured during cleaning showed an increasing tendency as pipe age increased. The methodology and results of this research are expected to contribute to the efficient maintenance and improvement of water quality in water distribution networks. Follow-up research involving the measurement of water quality at regular time intervals during cleaning would allow a more accurate comparison of discharge water quality characteristics and cleaning effects between different cleaning methods. To this end, it is considered necessary to develop a standardized manual that can be used in the field and to provide relevant trainings.

• Journal of the Korea Convergence Society
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• v.9 no.11
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• pp.209-216
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• 2018

This study aimed to investigate the association of the muscle activity around the neck of the operator(dental hygienists') according to the change in the patient's neck angle during a direct visual inspection on the maxillary right-side molar palatal surface. The operators were $4^{th}$ year dental hygiene students, who are future dentalhy gienists, having accurate understanding on and awareness of the location of the operation site, hand fixation, and how to use the tools. Data on the change in the muscle activity around the neck were collected by using surface electromyography and neck goniometer. SPSS statistics 20 was used for statistical analyses including Shapiro-wilk test and one-way ANOVA. As a result, the activities of the operator upper trapezius, cervical erector spinae, and levator scapulae muscles significantly decreased when the patient's head was angled compared to when it was not. For the angle of the operator head, the head bend significantly decreased when the patient's head was angled than when it was not. Based on the study results, it is expected that angling the patient's head when treating his or her teeth will decrease the excessive muscle activity around the neck of the operator, and will reduce muscle fatigue. Therefore, angling the head of the patient while treating his or her teeth is recommended. This suggests that muscle pain caused by repetitive actions in the wrong posture can be reduced.

• Atmosphere
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• v.29 no.1
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• pp.87-103
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• 2019

This study introduces the overall characteristics of LOVECLIM version 1.3, the earth system model of intermediate complexity (EMIC), including the installation and operation processes by conducting two kinds of past climate simulation. First climate simulation is the equilibrium experiment during the mid-Holocene (6,000 BP), when orbital parameters were different compared to those at present. The overall accuracy of simulated global atmospheric fields by LOVECLIM is relatively lower than that in Coupled Model Intercomparison Project phase 5 (CMIP5) and Paleoclimate modelling Intercomparison Project phase 3 (PMIP3) simulations. However, surface temperature over the globe, the 800 hPa meridional wind over the mid-latitude coastal region, and the 200 hPa zonal wind from LOVECLIM show similar spatial distribution to those multi-model mean of CMIP5/PMIP3 climate models. Second one is the transient climate experiment from mid-Holocene to present. LOVECLIM well captures the major differences in surface temperature between preindustrial and mid-Holocene simulations by CMIP5/PMIP3 multi-model mean, even though it was performed with short integration time (i.e., about four days in a single CPU environment). In this way, although the earth system model of intermediate complexity has a limit due to its relatively low accuracy, it can be a very useful tool in the specific research area such as paleoclimate.

• The Journal of the Korea Contents Association
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• v.22 no.9
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• pp.85-94
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• 2022

In modern society, environmental and energy problems have caused to replace cars with environment friendly energy. Vehicles with internal combustion engine which use petroleum are one of the factors that influence global pollution due to environment problems such as fine dust and ozone layer destruction. In addition use of energies for automobile making resources to become depleted. To solve this limited oil energy problem by using other energy sources. To the problem using electric energy and green energy as alternative for a solution. Among environment friendly energies this paper studies the possibility of drive service for autonomous vehicles that self-charges using only solar energy and whether they can be used as pollution free and alternative energy for automobiles. Studies was researched based on published literature review, data from ministry of transportation and automobile companies. Also case of electric vehicle and prototype automobile using only solar energy and the theory of near future technologies. Many automakers are using electric cars as alternative energy. Also making efforts to use solar energy as an substitute energy source and as a way to supplement electricity. Results show that there is a potential on operating autonomous vehicle using only solar energy. Furthermore, it will be possible to use automobiles actively, also use and supply solar energy. This paper suggest the possibility of contributing to the future of the automotive industry.

• Journal of IKEEE
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• v.26 no.4
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• pp.736-741
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• 2022

Lattice-based cryptography is the most practical post-quantum cryptography because it enjoys strong worst-case security, relatively efficient implementation, and simplicity. Ring learning with errors (R-LWE) is a public key encryption (PKE) method of lattice-based encryption (LBC), and the most important operation of R-LWE is the modular polynomial multiplication of rings. This paper proposes a method for optimizing modular multipliers based on approximate computing (AC) technology, targeting the medium-security parameter set of the R-LWE cryptosystem. First, as a simple way to implement complex logic, LUT is used to omit some of the approximate multiplication operations, and the 2's complement method is used to calculate the number of bits whose value is 1 when converting the value of the input data to binary. We propose a total of two methods to reduce the number of required adders by minimizing them. The proposed LUT-based modular multiplier reduced both speed and area by 9% compared to the existing R-LWE modular multiplier, and the modular multiplier using the 2's complement method reduced the area by 40% and improved the speed by 2%. appear. Finally, the area of the optimized modular multiplier with both of these methods applied was reduced by up to 43% compared to the previous one, and the speed was reduced by up to 10%.

• Journal of The Korean Association of Information Education
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• v.26 no.5
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• pp.427-437
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• 2022

The purpose of this study is to examine elementary school teachers' perceptions of digital textbooks to gain insight into the development of digital textbooks. To this end, first, eight functions of the digital textbook were set, and two to six detailed functions were set for each function. Afterwards, based on this function, 372 elementary school teachers across the country were asked to ask about their perception of digital competence, their experience of using digital textbooks after COVIE-19 and their perception of digital textbooks. A simple regression analysis was used to examine the perception of digital textbooks according to the perception of digital competence and a one-way distribution analysis method was used to analyze the perception of digital textbooks according to the experience of using digital textbooks. The analysis found that elementary school teachers' confidence in their digital competence had a positive effect on all components of digital textbooks. In particular, the teachers' higher confidence in digital competence led to the increased need for 'operation and management' functions. In addition, the teachers who frequently use digital textbooks perceived a higher need for digital textbook components except for 'searching' and 'Authoring Tools Support' than teachers who do not use them. This paper shows that it is necessary to positively induce elementary school teachers' perceptions of digital competence and encourage using digital textbooks to successfully increase the usage of digital textbooks in classes.

• Economic and Environmental Geology
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• v.57 no.2
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• pp.177-184
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• 2024

This study was conducted to find a way to reduce the production of cakes generated in the domestic aggregate production process. Cakes from 8 wet aggregate producers were collected and particle size was analyzed. Samples were collected step by step from an aggregate producer A, particle size analysis was performed, and the material balance was calculated before and after an sand recovery unit by modeling the production process. As a result of the particle size analysis of eight cakes, one sample contained 50% sand, and the rest contained about 5% to 25% sand. The results showing that the cake contained a variety of sand in cakes may indicate that the recovery efficiency of the sand recovery units in the field varied. Sieve analysis of the samples showed that the generation of sand particles increased 2.8 times during the third crushing compared to the second crushing, and more cake particles were generated. As a result of simulating the sand recovery unit model, the lower the cut point of the cyclone and dewatering screen, the higher the sand production and the less cake production appeared. In order to reduce the production of cake in the field, it was determined that an optimal operation of the sand recovery unit was necessary in the aggregate production process.

• The Korean Society of Law and Medicine
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• v.20 no.3
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• pp.143-174
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• 2019

Our Constitution obliges the state to protect the health of the people, and the Medical Law, which embodied Constitution, sets out in detail the matters related to open the medical institution, and one of them is to prohibit the operation of multiple medical institutions. By the way, virtually multiple medical institutions could be opened and operated because the Supreme Court had interpreted that several medical institutions could be opened if medical activities were not performed directly at the additional medical institution which was opened under the another doctor's license. However, some health care providers opened the several medical institutions with another doctor's license for the purpose of the maximization of profit, and did illegal medical cares like the unfair luring of patients, over-treatment, and commission treatment. Also, realistic problems such as the infringed health rights have arisen. Accordingly, lawmakers had come to amend the Medical Law to readjust the system of opening for medical institution so that medical personnel could not open or operate more than one medical institution for any reason. For this reason, the Constitutional Court recently declared a constitutional decision through a long period of in-depth deliberation because the constitutional petition and the adjudication on the constitutionality of statutes had been filed on whether Article 33 paragraph 8 of the revised medical law is unconstitutional. The Constitutional Court acknowledged the "justice of purpose" in view of the importance of public medical institutions, of the prevention from seduction of for-profit patients and from over-treatment, and of the fact that health care should not be the object of commercial transactions. Given the risk that medical personnel might be subject to outside capital, the concern that the holder of the medical institution's opening certificate and the actual operator may be separated, the principle that the human body and life should not be just a means, and the current system's inability to identify over-treatment, it also acknowledged the 'minimum infringement'. Furthermore, The Constitutional Court judged it is constitutional in compliance with the principle of restricting fundamental rights, such as 'balance of legal interests'. In this regard, legislative complements are needed in order to effectively prevent the for-profit management and the over-treatment the Constitutional Court is concerned about. In this regard, consumer groups actively support the need for legislation, and health care providers groups also agree on the need for legislation. Therefore, the legislators should respect the recent Constitutional Court's decision and in the near future complete the complementary legislation to reflect the people's interests.