• Smart Media Journal
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• v.9 no.3
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• pp.71-79
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• 2020

Mobile network is used by many users worldwide for diverse services, including phone-call, messaging and data transfer over the Internet. However, this network may experience massive damage if it is exposed to cyber-attacks or denial-of-service attacks via wireless communication interference. Because the mobile network is also used as an emergency network in cases of disaster, evaluation or verification for security and safety is necessary as an important nation-wide asset. However, it is not easy to analyze the mobile core network because it's built and serviced by private service providers, exclusively operated, and there is even no separate network for testing. Thus, in this paper, a virtual mobile network is built using OpenAirInterface, which is implemented based on 3GPP standards and provided as an open source software, and the structure and protocols of the core network are analyzed. In particular, the S1AP protocol messages captured on S1-MME, the interface between the base station eNodeB and the mobility manager MME, are analyzed to identify potential security threats by evaluating the effect of the messages sent from the user terminal UE to the mobile core network.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.984-987
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• 2013

In concept, such as the backup of wired network and disaster prevention network of water treatment measurement and control system, reliability and security of high level of sending and receiving data between the nodes must be ensured in Ad-hoc network construction. Rather than apply the common communication protocols of Ad-hoc network construction during the FA network of closed water treatment facility with the facility of a certain scale is concentrated contrast, and high characteristics of the water treatment system infrastructure, public facilities We have developed a specific protocol another that applies the OTP of communication frame of process control commands and H-ARQ with ZRP by applying the flexibility to time constraints such as precision industrial plants to ensure the safety and property of facility operation.

• 한국노년학
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• v.41 no.3
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• pp.353-371
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• 2021

The purpose of this study is to provide clues to social welfare policy making by revealing discourse on social intervention and response based on big data on elderly living alone in the COVID-19 situation. Keyword analysis, network analysis, and topic analysis were utilized to explore the ways in which news media have portrayed challenges facing older individuals and the ways in which the central and local government as well as private organization have responded to them. Results are as follows. First, networks(degree, closeness, betweenness) were formed around region, delivery, society, support, and vulnerability, suggesting an increased demand for economic assistance and social support as well as stronger service delivery systems. Second, key topics derived included "establishing public delivery systems", "establishing local networks", "Managing care gap", "Establishing a private economic support system", and "Establishing service organization system". Based on the research results, discourse on the organic role of government, communities and the private sector has been presented, suggesting policy and practical implications by proposing a discussion on how to intervene for elderly living alone in disaster situations such as COVID-19.

• Journal of Advanced Navigation Technology
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• v.24 no.2
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• pp.67-72
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• 2020

Satellite communication is not used by many people like mobile communication, but it is a necessary technology for public service and communication services, such as providing the Internet in military, disaster, remote education and medical services, island areas, and infrastructure vulnerable areas. However, on ships and aircraft, mobile communications requiring base stations are either unavailable or restricted in their use. In this paper, we used a Raspberry Pi board as the terminal device to communicate network through satellite modem and PPP protocol, and implemented two-way data link using the text message of the modem to connect to the Thuraya geo-stationary orbit network. In addition, I/O devices were connected to the controller of the terminal equipment to design and implement an IoT device system for ships that can remotely access the system under control and control I/Os and transmit measured data through various sensors.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.306-307
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• 2018

본 논문에서는 해양관측부이 보호 및 해상 관측 등을 위해 사용되고 있는 국내외 영상감시 시스템 및 기술 현황을 살펴보고, 차세대 해상용 통신 네트워크 및 인공위성을 통한 해양 공공시설의 안전감시 시스템이 가져야 할 요구사항과 이에 대한 국내외 기술개발 현황을 살펴본다. 또한, 선박 인식 및 추적, 나아가 충돌 예측 등을 수행하여, 해상사고를 예방할 수 있는 해양관측부이용 감시시스템의 개발에 관한 내용을 다룬다. 이를 위해 개발하는 시스템은 해양관측부이에 장착되어 저전력으로 동작하며, 해수에 강한 트레일 감시카메라를 개발하여 적용한다. 추가적으로 AIS정보를 활용한 충돌 예방 경고 모듈이 탑재되고, LTE-M 등과 같은 차세대 해상이동통신 및 위성망 M2M 네트워크를 응용한 통신 모듈을 기반으로 육상 알람 기능을 제공한다. 이를 통해 시스템의 신뢰성을 확보하고, 대형 선박과의 해상사고(선박추돌사고 및 기름유출 등)와 소형선박에 의한 시설물 훼손(Vandalism)의 발생 가능성을 인지할 수 있는 종합적인 데이터를 수집하여 사고의 예방 및 재난 상황 등을 예측함으로써 중요시설의 안전 및 해양환경 보호에 기여하고자 한다.

• Journal of Internet Computing and Services
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• v.21 no.6
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• pp.1-12
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• 2020

Low-Orbit satellite mobile networks can provide services through miniaturized terminals with low transmission power, which can be used as reliable means of communication in the national public disaster network and defense sector. However, the high traffic environment in the emergency preparedness situation increases the new call blocking probability and the handover failure probability of the satellite network, and the increase of the handover failure probability affects the QoS because low orbit satellites move in orbit at a very high speed. Among the channel allocation methods of satellite communication, the FCA shows relatively better performance in a high traffic environment than DCA and is suitable for emergency preparedness situations, but in order to optimize QoS when traffic increases, the new call blocking and the handover failure must be minimized. In this paper, we propose LEO-DBC (LEO satellite dynamic beam width control) technique, which improves QoS by adaptive adjustment of beam width of low-orbit satellites and call time of terminals by improving FCA-QH method. Through the LEO-DBC technique, it is expected that the QoS of the mobile satellite communication network can be optimally maintained in high traffic environments in emergency preparedness situations.