• Journal of Korean Society of Water and Wastewater
• /
• v.33 no.5
• /
• pp.329-339
• /
• 2019

Recently, the advancement of information and communication technology(ICT) is expanding the connectivity through Internet of Things(IoT), and the media of connection is also expanding from wire/cable transmission to broadband wireless communication, which has significantly improved mobility. This hyperconnectivity has become a key element of the fourth industrial revolution, whereas the supervisory control network of purification plants in korea is operated as a communication network separated from the outside, thereby lagging in terms of connectivity. This is considered the best way to ensure security, and thus there is hardly any consideration of establishing alternatives to operate an efficient and stable communication network. Moreover, security for management of a commercialized communication network and network management solution may be accompanied by immense costs, making it more difficult to make new attempts. Therefore, to improve the conditions for the current supervisory control network of purification plants, this study developed a industrial security L2 switch that supports modbus TCP(Transmission Control Protocol) communication and encryption function of the transmission section. As a result, the communication security performance improved significantly, and the cost for implementing the network management system using Historical Trend and information of HMI(Human Machine Interface) could be reduced by approximately KRW 200 million. The results of this study may be applied to systems for gas, electricity and social safety nets that are infrastructure communication networks that are similar to purification plants.

• The Journal of Internal Korean Medicine
• /
• v.42 no.4
• /
• pp.563-571
• /
• 2021

Objectives: This pilot study aimed to confirm the possibility of applying our design to the main study, a retrospective medical record analysis of the diseases which have most frequently been treated with collaborations of Korean and Western medicine, and to identify what corrections and statistical models are needed to conduct the main study. Methods: Data were collected from a case report form developed for patients who received treatment in the medical institutions. Appropriate statistical techniques, like Propensity Score (PS) and Generalized Estimation Equation (GEE) models, were used to compare the indicators of collaboration and non-collaboration groups for patients in comparable diseases. Results: Using PS matching for each M and S disease group, the indicators were compared by balancing the collaboration and non-collaboration group, and the GEE models compared indicators between groups in each disease over follow-up. Through this process we identified two limitations, insufficient samples and a large deviation of the follow-up period. Conclusion: This pilot study confirmed that the study design and case report form are applicable. The main study will be conducted by collecting sufficient samples and reflecting deviation of follow-up period.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.13 no.3
• /
• pp.1502-1522
• /
• 2019

Leakage of secret keys may be the most devastating problem in public key cryptosystems because it means that all security guarantees are missing. The forward security mechanism allows users to update secret keys frequently without updating public keys. Meanwhile, it ensures that an attacker is unable to derive a user's secret keys for any past time, even if it compromises the user's current secret key. Therefore, it offers an effective cryptographic approach to address the private key leakage problem. As an extension of the forward security mechanism in certificate-based public key cryptography, forward-secure certificate-based signature (FS-CBS) has many appealing merits, such as no key escrow, no secure channel and implicit authentication. Until now, there is only one FS-CBS scheme that does not employ the random oracles. Unfortunately, our cryptanalysis indicates that the scheme is subject to the security vulnerability due to the existential forgery attack from the malicious CA. Our attack demonstrates that a CA can destroy its existential unforgeability by implanting trapdoors in system parameters without knowing the target user's secret key. Therefore, it is fair to say that to design a FS-CBS scheme secure against malicious CAs without lying random oracles is still an unsolved issue. To address this problem, we put forward an enhanced FS-CBS scheme without random oracles. Our FS-CBS scheme not only fixes the security weakness in the original scheme, but also significantly optimizes the scheme efficiency. In the standard model, we formally prove its security under the complexity assumption of the square computational Diffie-Hellman problem. In addition, the comparison with the original FS-CBS scheme shows that our scheme offers stronger security guarantee and enjoys better performance.

• Journal of the Korea Convergence Society
• /
• v.10 no.10
• /
• pp.197-205
• /
• 2019

The purpose of this research was examining the effects of problem-based learning strategies(PBL) on problem solving skill conducted in Korea, using meta-analysis technique. This meta-analysis reviewed the results of 41 studies published between 1998 and 2017 in Korea. The overall weighted mean effect size value was .753 with .064 standard error which was calculated by random effects model. PBL strategies have been found to be more effective in mathematics course (d=.922), art course (d=.916), practical art course (d=.827), E-PBL (d=.791) and middle school level (d=.972). As PBL exhibit a substantial effect on students' problem solving skill, it is recommended that teachers should learn how to implement these strategies in their lesson. PBL is expected to contribute to the improvement of teaching methods as the learning environment changes during the 4th Industrial Revolution.

• Education of Primary School Mathematics
• /
• v.24 no.2
• /
• pp.103-114
• /
• 2021

In this study I recognized the problems with the use of the terms 'quotient' and 'reminder' in the division of decimal and explored ways to improve them. The prior studies and current textbooks critically analyzed because each researcher has different views on the use of the terms 'quotient' and 'reminder' because of the same view of the values in the division calculation. As a result of this study, I proposed to view the result 'q' and 'r' of division of decimals by division algorithms b=a×q+r as 'quotient' and 'reminder', and the amount equal to or smaller to q the problem context as a final 'result value' and the residual value as 'remained value'. It was also proposed that the approximate value represented by rounding the quotient should not be referred to as 'quotient'.

• The Mathematical Education
• /
• v.61 no.4
• /
• pp.631-651
• /
• 2022

It has been alerted that Korean students' mathematical affective achievement is very low. In order to solve this problem, various policies related to mathematical affective domains have been promoted, but it is necessary to examine various existing policies and explore the direction for improving them in more essential aspects. Based on previous studies that the growth mindset helps to increase students' affective achievement, this study focused on improving students' math-related growth mindset and ultimately exploring policies that can increase mathematical affective achievement. Therefore, the current status of mathematical affective achievement of Korean students was examined, and the policies and related cases in the mathematical affective domain were investigated. Based on the results, some keywords were derived and then the directions of policy for improving the math-related growth mindset and the affective achievement of students were suggested.

• Journal of The Korean Association of Information Education
• /
• v.25 no.2
• /
• pp.317-325
• /
• 2021

In this paper, the degree of reflection of SW·AI elements and CT elements was investigated and analyzed for a total of 44 textbooks of Korean, social, moral, mathematics and science textbooks based on the 2015 revised curriculum. As a result of the analysis, most of the activities of data collection, data analysis, and data presentation, which are ICT elements, were not reflected, and algorithm and programming elements were not reflected among SW·AI content elements, and there were no abstraction, automation, and generalization elements among CT elements. Therefore, in order to effectively implement SW·AI convergence education in elementary school subjects, we will expand ICT utilization activities to SW·AI utilization activities. Training on the understanding of SW·AI convergence education and improvement of teaching and learning methods using SW·AI is needed for teachers. In addition, it is necessary to establish an information curriculum and secure separate class hours for substantial SW·AI education.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.19 no.3
• /
• pp.3-10
• /
• 2009

In this paper, we introduce improved differential and linear attacks on the SMS4 block cipher which is used in the Chinese national standard WAPI (WLAN Authentication and Privacy Infrastructure, WLAN - Wireless Local Area Network): First, we introduce how to extend previously known differential attacks on SMS4 from 20 or 21 to 22 out of the full 32 rounds. Second, we improve a previously known linear attack on 22-round reduced SMS4 from $2^{119}$ known plaintexts, $2^{109}$ memory bytes, $2^{117}$ encryptions to $2^{117}$ known plaintexts, $2^{l09}$ memory bytes, $2^{112.24}$ encryptions, by using a new linear approximation.

• Journal of Digital Convergence
• /
• v.19 no.6
• /
• pp.29-38
• /
• 2021

The social studies, mathematics, and science textbooks of the elementary curriculum will begin to be authorized from 2022. This study explores the effect of textbooks based on a gamification motivation strategy on learner interest. For this purpose, this study analyzes whether the systematic application of the gamification motivation strategy to elementary studies textbooks, which will be authorized from 2022, can develop this textbook into a "learner-centered curriculum book that induces interest." More specifically, this study applied Kumsung Publishing's experimental social studies textbooks in class and conducted a questionnaire among 121 third graders to verify the effectiveness of the textbooks. The results show that studies textbooks based on a gamification motivation strategy greatly influence increased learner interest in the classroom. The textbooks also represent a positive influence in learner understanding, interest, and curiosity regarding the class content and assistance. Demonstrating that gamification motivation strategy is worthwhile to actively apply in future textbook development for the enhancement of learners' interests, this study is significant in that it has presented a meaningful textbook development model.

• Korean Journal of Community Nutrition
• /
• v.27 no.5
• /
• pp.361-372
• /
• 2022

Objectives: The purpose of this study was to explore the effectiveness of the STEAM (Science, Technology, Engineering, Arts, and Mathematics) education program on the use of specific food groups in improving nutrition-related knowledge and attitude, dietary behavior, creative problem solving, and STEAM attitude. Methods: We selected two classes at a kindergarten in Jeollabuk-do, South Korea. A total of 44 kindergarteners from the two classrooms participated in this study. The experimental group and the control group were formed with 22 students each. The experimental group attended 11 STEAM classes on the use of the grain, fruit, and milk food groups. First, we performed the paired t-test to examine changes from pre-to-post classes for both groups. Then, we used ANCOVA to compare post-test scores between the experimental and control groups with the adjustment of pre-test scores. Results: The results demonstrate that the STEAM education program on the use of the food groups significantly improved (1) nutrition-related knowledge and attitude, and dietary behavior (P < 0.001), (2) creative problem solving (P < 0.001), and (3) STEAM attitude (P < 0.001) in the intervention group when compared with the control group. Conclusions: The STEAM education program on the use of food groups is effective in enhancing nutrition knowledge and attitude, dietary behavior, creative problem solving, and STEAM attitudes among kindergarten students.