• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.5
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• pp.49-63
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• 2019

Crowdedness management at subway platforms is essential to improve services, including the prevention of train delays and ensuring passenger safety. Establishing effective crowdedness mitigation measures for platforms requires accurate estimation of the congestion level. There are temporal and spatial constraints since crowdedness on subway platforms is assessed at certain locations every 1-2 years by hand counting. However, smart cards generate real-time big data 24 hours a day and could be used in estimating congestion. This study proposes a model based on data from transit cards to estimate crowdedness dynamically. Crowdedness was defined as demand, which can be translated into passengers dynamically moving along a subway network. The trajectory of an individual passenger can be identified through this model. Passenger flow that concentrates or disperses at a platform is also calculated every minute. Lastly, the platform congestion level is estimated based on effective waiting areas for each platform structure.

• Convergence Security Journal
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• v.19 no.1
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• pp.3-10
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• 2019

The 5G network is a next-generation converged network that combines various ICT technologies to realize the need for high speed, hyper connection and ultra low delay, and various efforts have been made to address the security vulnerabilities of the previous generation mobile networks. However, the standards released so far still have potential security vulnerabilities, such as USIM deception and replication attack, message re-transmission attack, and race-condition attack. In order to solve these security problems, this paper proposes a new 5G-AKA protocol with PUF technology, which is a physical unclonable function. The proposed PUF-based 5G-AKA improves the security vulnerabilities identified so far using the device-specific response for a specific challenge and hash function. This approach enables a strong white-list policy through the addition of inexpensive PUF circuits when utilizing 5G networks in areas where security is critical. In addition, since additional cryptographic algorithms are not applied to existing protocols, there is relatively little burden on increasing computational costs or increasing authentication parameter storage.

• Journal of Digital Convergence
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• v.17 no.5
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• pp.41-49
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• 2019

This study aims to investigate the awareness and status of smart attendance systems in the professors and college students who directly use an electronic smart system, a learning management system utilizing IT and to propose a plan for improvement to increase the efficiency of the smart attendance system. As for the research method, this study conducted an online survey with 264 students at S. University to investigate the status of their use and awareness of the smart attendance system. As a result, first, the professors mostly were satisfied with the smart attendance system, and it would be necessary to improve learning ability and the function of self-management in connection with the learning management system. Second, the college students were dissatisfied with the user interface and speed of the smart attendance system, and it would be necessary to improve the delay time, login, update, and false attendance.

• Journal of Digital Convergence
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• v.17 no.4
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• pp.249-254
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• 2019

As an alternative to the growing problem of weather anomalies, users are using mobile weather apps to predict the weather. Even though it provides clear information, the user makes mistakes in forecasting the weather. For this reason, The purpose of this study is to find elements that can be prepared for the volatile weather through mobile application. Jakob Nielsen's "heuristic" evaluation found weaknesses in the application. Then I proceeded to analyze it from a behavioral economics standpoint. As a result, the two applications had various functions and accurate information. However, user accessibility was low and focused on 'information delivery'.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.1
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• pp.81-92
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• 2009

Recently, there is a drastic increase in users interested in real-time multimedia services in the WLAN environment, as the demand of IEEE 802.11 WLAN-based services increases. However, the handoff delay based on 802.11i security policy is not acceptable for the seamless real-time multimedia services provided to MS frequently moving in the WLAN environment, and there is a possibility of DoS attacks against session key derivation process and handoff mechanism. In this paper, a secure and efficient handoff mechanism in the centralized WLAN environment is introduced to solve the security problems. The 4-way Handshake for both mutual authentication and session key derivation is replaced by the 2-way Reassociation process.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.2
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• pp.213-224
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• 2012

The integrated core network architecture and various mobile subscriber behavior can result in a significant increase of signaling load inside the evolved packet core network proposed by 3GPP in Release 8. Consequently, an authentication signaling analysis can provide insights into reducing the authentication signaling loads and latency, satisfying the quality-of-experience. In this paper, we evaluate the signaling loads in the EPS architecture via analytical modeling based on the renewal process theory. The renewal process theory works well, irrespective of a specific random process (i.e. Poisson). This paper considers various subscribers patterns in terms of call arrival rate, mobility, subscriber's preference and operational policy. Numerical results are illustrated to show the interactions between the parameters and the performance metrics. The sensitivity of vertical handover performance and the effects of heavy-tail process are also discussed.

• Journal of The Korean Association For Science Education
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• v.42 no.2
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• pp.185-200
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• 2022

The purpose of this study is to understand the trends and changes of the articles publishing the Journal of the Korean Association for Science Education(JKASE) in the past forty-four years. To this end, Latent Dirichlet Allocation(LDA) topic modeling analysis was performed on a total of 2,115 English abstracts of papers published in the JKASE from 1978 to 2021. As a result of LDA topic modeling analysis, a total of 23 topics were extracted, and each topic was presented with its related keywords and articles. Next, in order to examine how these topics have changed over time, we visualized the average weights of each topic for a 4-year cycle by using heatmaps. The topics that have risen or fallen were identified. The results of this study provide new insights into science education research in Korea in terms of revealing not only traditional research topics that have been consistently studied but also the topics that have changed in response to the development of educational philosophy or research methods, social or policy demands related to science education.

• Journal of Digital Convergence
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• v.20 no.4
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• pp.565-573
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• 2022

This study aims to analyze the preference factors of the Korean MZ generation with regards to the online programs developed by museums abroad during the COVID-19 pandemic. World renown museums such as the British Museum, the National Gallery of London, Van Gogh Museum, J. Paul Getty Museum, Hasting Contemporary, Uffizi Gallery, and the Guggenheim Museum tackled the social-distancing situation with various creative online programs and events to continue their role as socially relevant institutions. Ten acclaimed programs conducted by these museums were shown to the Korean MZ generation, the most digitally savvy and frequent visitors to museums, to extract their responses to the various types of programs. The study showed that the Korean MZ generation prefer online programs which most closely reflect the onsite experience of a museum, and online contents with educational elements.

• Journal of the Korea Society of Computer and Information
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• v.27 no.7
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• pp.9-16
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• 2022

Today, with the advent of the 4th industrial revolution, IoT (Internet of Things) systems are advancing rapidly. For this reason, a various application with high-performance and large-capacity are emerging. Therefore, there is a need for low-power and high-performance memory for computing systems with these applications. In this paper, we propose an effective structure for the L1 cache memory, which consumes the most energy in the computing system. The proposed cache system is largely composed of two parts, the L1 main cache and the buffer cache. The main cache is 2 banks, and each bank consists of a 2-way set association. When the L1 cache hits, the data is copied into buffer cache according to the proposed algorithm. According to simulation, the proposed L1 cache system improved the performance of energy delay products by about 65% compared to the existing 4-way set associative cache memory.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.4
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• pp.353-366
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• 2021

Objectives: An appropriate level of cost support is being proposed to maximize the participation rate. In addition, as the amount of support is highly concentrated at the level of the limit under the current level of supports, the level of cost support is low when the actual level of cost of measuring the working environment exceeds the limit. This paper describes the adjustment of an appropriate cost support rate. Methods: First, this paper analyzes the current cost support status using data from the KOSHA. Second, an alternative for adjusting the cost support rate is presented in consideration of the incentive aspect. Third, we present simulation results for the average cost support rate, the impact of each alternative on finance, and more. Fourth, the most desirable adjustment method is presented after comparing and analyzing the results of various alternatives. Results: In this paper, we present a new scale model. This model is a mixture of flat-rate, fixed rate, and subside cap. It is expected that the new model will not only facilitate participation in businesses with low measurement costs, but also have the effect of controlling measurement costs for institutions that incur greater costs. It is also expected that setting a cap will have the effect of considering government finances and inducing excessively costly institutions to reduce costs. Thus, the new model is likely to be superior to others. If the fourth plan is applied to new businesses and the fifth plan is applied to sustainable businesses, the average cost support rates will be 87.68 percent and 65.18 percent, respectively, and the needed finances will be 2.5 billion won, 18.8 billion won, and 21.3 billion won in total. Conclusions: It seems most desirable to introduce a new model that combines flat-rate, fixed-rate, and subsidy cap systems and achieve an appropriate cost support rate through this model.