• Pediatric Infection and Vaccine
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• v.28 no.2
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• pp.57-65
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• 2021

School closures during the coronavirus disease 2019 (COVID-19) pandemic have been outlined in studies from different disciplines, including economics, sociology, mathematical modeling, epidemiology, and public health. In this review, we discuss the implications of school closures in the context of the current COVID-19 pandemic. Modeling studies of the effects of school closures, largely derived from the pandemic influenza model, on severe acute respiratory syndrome coronavirus 2 produced conflicting results. Earlier studies assessed the risk of school reopening by modeling transmission across schools and communities; however, it remains unclear whether the risk is due to increased transmission in adults or children. The empirical findings of the impact of school closures on COVID-19 outbreaks suggest no clear effect, likely because of heterogeneity in community infection pressure, differences in school closure strategies, or the use of multiple interventions. The benefits of school closings are unclear and not readily quantifiable; however, they must be weighed against the potential high social costs, which can also negatively affect the health of this generation.

• The KIPS Transactions:PartD
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• v.16D no.5
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• pp.767-790
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• 2009

Setting up a priorityfor an embedded system is greatly significant because a release plan at the early stage of product developments can properly be established through right decision making procedures based on the priorities. For instance, both dependencies among requirements and the aspects of product developers should be considered into the priorities to improve the embedded system. Especially, trade-offs among the requirements, which are quite different depending on H/W and S/W architecture styles they use, should be acknowledged without exception. However, the selection process on the priority has hitherto been fairly systematic in the existing environment where hardware and software are not being considered at once. Therefore, this paper suggests an dependency and aspect-based model and process for the requirements of the priority. For this, the paper analyzes the trade-offs between the requirements depending on the disparate Architecture styles of H/W and S/W, and it also reflects the viewpoints of the developers. For thelast thing, the model and process suggested will be applied to the case of the development of both cell phones and cameras to gain authenticity and reliability. In conclusion, the danger occurring when the release plan is constructed can be minimized by screening the priorities that optimizes the embedded system more explicitly.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.11A
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• pp.1128-1137
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• 2007

Recently, according to being advanced internet, mobile communication technique, Telematics environment which users in vehicle can use internet service in LAN(Local Area Network) via mobile device has being realized. In this paper, we propose the remote user authentication protocol to solve these issues. Additionally, we use biometrics(fingerprint) for our user authentication protocol cause it can provide to avoid critical weakness that can be lost, stolen, or forgotten and to make authentication easily. In our user authentication protocol, to protect the biometric we use session key which is generated from master key distributed in our key distribution protocol. In particular, we propose secure protocol between APs considering weakness of security in mobile environment. Based on implementation of our proposed protocol, we conform that our proposed protocols are secure from various attack methods and provide real-time authentication.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.1
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• pp.98-108
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• 2013

The number of Hi-Pass lanes became 793 lanes at 316 expressway tollgates in 2011 due to the increase in the Hi-Pass use. In spite of the increase in the number of Hi-Pass lanes, there have been increased potential risks in tollgates where vehicles using a Hi-Pass lane must weave with other vehicles using a TCS lane. Therefore, there is a need for study on the safety in tollgates. To this end, this study aims at developing a methodology to evaluate the performance measures of diverse location countermeasures of Hi-Pass lanes in an efficient and systematic way. This study measured the mobility, safety and the convenience of installation and operation of Hi-Pass lanes using a microscopic traffic simulation tool, the surrogate safety assessment model and survey. In addition, this study aggregated the above three performance indexes using weight factors estimated using the AHP technique. For the test site, Dongsuwon interchange was selected. After building the microscopic traffic simulation model for the test site, the location countermeasures of Hi-Pass lanes applicable to the test site were compared with each other in terms of the mobility, safety and installing and operating convenience. As a result, there has been no apparent difference in mobility index based on delays. However, the countermeasures where Hi-Pass lanes are located in inside lanes generally showed better safety performance based on the number of conflicts. In addition, countermeasures with neighboring Hi-Pass lanes were favorable in terms of the safety and the convenience of installation and operation. The methodology proposed in this study was found to be useful to support decision makings by providing critical and quantitative information regarding the mobility, safety and the convenience of installation and operation.

• Journal of Digital Convergence
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• v.13 no.8
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• pp.473-481
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• 2015

The flood and environment surveillance network on riverside is a network requiring a way to efficiently manage the information from all kinds of sensors, along with an optical communication device that can deliver high-quality video information at high speed. Since on-site prompt recovery is very important especially for communication problems that occurred due to cut-off or aged network, various researches have been carried out on this. However, because the security against outside hacking or outside intrusion with illegal purposes is very important for environment surveillance network, such as the national backbone network, an efficient network maintenance and repair should be enabled while satisfying security and reliability at the same time. A characteristic of requirement is that when security is improved, the efficiency of maintenance and repair drops as they are conflicting to each other. Therefore, this research proposed a system in order to satisfy the conflicting requirement and improve security, by developing a one-way Bypass TAP and an android-based smartphone app that can enable efficient network maintenance and repair.

• Journal of Korean Society of Transportation
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• v.31 no.4
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• pp.58-66
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• 2013

Due to the characteristics of urban freeways such as heavy traffic and high speed, work zone on urban freeways causes the increase of not only the likelihood of crash occurrence but also traffic congestion caused by lane drop, lane change, acceleration/deceleration, and etc. This paper aims to determine the proper length of transition area that satisfies two criteria, mobility and safety, to make the operation of work zone more efficient. For the analysis, three different scenarios were developed by the number of lanes and the proper length of transition area were determined by changing the length from 100m to 500m in 100m increments. The results showed that the proper length of transition area for 3- and 4-lane freeways is 300m, whereas the proper length of 2-lane freeways is 200m. The results indicated that the different length of transition area based on the number of lanes is more desirable and efficient.

• Journal of International Area Studies (JIAS)
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• v.19 no.1
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• pp.157-204
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• 2015

This paper explores firm-specific internal and external determinants of the sustainability of "the social innovative enterprise(SIE)" by conducting a case research on Fragrant People Co. In doing so, some business and policy implications have been produced concerning the components and determinants of the sustainability of the SIE. First, entrepreneurship is a necessary factor for the survival and growth of the SIE. A social entrepreneur does manage effectively social and economic opportunities for making economic and social values interact dynamically beyond their trade-off relationship and creating new market chances. Second, the SIE also needs competitive advantages as commercial enterprises do. Valuable resources to be used for taking opportunities and avoiding threats, rare resources not to be possessed by other firms, and resources not to be easily imitated by competitors are extremely necessary for achieving objectives of the SIE. In addition, a firm must be well organized for those valuable, rare, and not easily imitated resources. Economic performance achieved by the SIE gives a birth to its financial independence, contributing to the realization of symmetric social performance. Third, the SIEs will be allowed to seek symmetrically economic and social performance only when they use sufficiently competitive advantage resources with entrepreneurship, which is composed of innovativeness, proactiveness, agility and risk-taking attitudes. In doing so, financial assistance from central or local governments may not ensure the sustainability of the SIEs. In addition, vision & value sharing(person-organization fit) can ensure the sustainability of the SIEs only when it is connected with the organizational commitment.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.3
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• pp.14-27
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• 2020

Pedestrian deaths account for a high percentage of deaths in traffic accidents in Korea, raising interest in pedestrian safety policy. However, since the walk signal time is applied based on the length of the crosswalk without considering the walker and the signal cycle, the walk waiting time is relatively longer than the crosswalk, causing pedestrian jaywalking. In this study, due to an unreasonable signal time plan during a road crossing where a signal is installed, the pedestrian's walk signal was given twice a cycle of crossings, and the operational and safety effects of the signal system were quantitatively and qualitatively analyzed, and the operational effects of the signal interval and jaywalking rate were assessed by different signal intervals. The results showed that jaywalking and waiting time decreased, and the shorter the interval between the application of the walk signal time, the less jaywalking is analyzed. However, there is a risk of vehicle conflict due to pedestrian exposure, and measures for expanding safety for operation were proposed.

• Journal of Korean Society of Transportation
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• v.27 no.3
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• pp.59-70
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• 2009

This study presents a novel traffic information system which is capable of detecting unsafe traffic events leading to accident occurrence and providing warning information to drivers for safer driving. Unsafe traffic events are captured by a vehicle image processing-based detection system in real time. Surrogate safety measures (SSM) representing quantitative accident potentials were derived, and further utilized to develop a data processing algorithm and analysis techniques in the proposed system. This study also defined 'emergency warning area' and 'general warning area' for more effective provision of warning information. In addition, methodologies for determining thresholds to trigger warning information were presented. Technical issues and further studies to fully exploit the benefits of the proposed system were discussed. It is expected that the proposed system would be effective for better management of traffic flow to prevent traffic accidents on freeways.

• Fire Science and Engineering
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• v.16 no.2
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• pp.43-50
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• 2002

21C, Multiplex Cinema Theater is made from movie industry developed and become a place where we can spend our free time and consuming. But, theater users, who are many and unspecified persons, are short of information on the Multiplex Cinema Theater, so that they may be injured or killed at the occurrence of fire accident. Particularly, Multiplex Cinema Theater is a place that underground space or top floor in highrise building had many people in theaters. However, this problem is difficult to solve that to protect human being and properties at the occurrence of fire accident in the Multiplex Cinema Theater, In order to overcome such problems, Multiplex Cinema Theater need fire protection solutions facilities concerning particulars to pay attention to the safety on a fire and evacuation. This study analysed Multiplex Cinema Theater concept and computer simulation for risk point.