• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2021.11a
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• pp.34-36
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• 2021

미래 해상환경에 대응하기 위해 기존 항로표지의 기술 및 역할에 ICT 기술을 융합하여 스마트한 해양 서비스 제공을 위한 노력이 계속되고 있다. 본 논문에서는 현 항로표지 통신 시스템의 문제점을 분석하고 스마트 항로표지 시설 고도화를 위한 최적의 통신 시스템 및 다중 통신 플랫폼 개발 방향을 제시하도록 한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.277-279
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• 2023

본 논문에서는 스마트항로표지 플랫폼 및 MIoT 시스템 형상에 대하여 고찰한다. 이러한 MIoT 시스템을 기반으로 항로표지의 집약 관리를 구현하고자 할 때 시스템 동작 형상에 대하여 살펴보도록 한다. 또한 MIoT 단말 형상에 대하여 검토하고 그동안 항로표지 집약 관리 현장의 단말에 대한 의문 사항을 정리하도록 한다.

• Electronics and Telecommunications Trends
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• v.31 no.5
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• pp.11-20
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• 2016

사물인터넷은 다양한 응용 및 융합 서비스를 창출할 새로운 기회의 장으로 떠오르고 있다. 가트너 등의 시장 조사기관 및 전문가 들의 예측에 따르면 2020년까지 사물인터넷 디바이스는 300~500억 대로 증가할 것이며, 시장 규모는 3,000억 달러를 초과할 것으로 전망하였다. 이러한 거대한 규모의 시장 선점을 위한 기술 간, 업체 간 경쟁도 한층 증대되고 있다. 비 3GPP 계열 LPWA 네트워크는 유럽을 중심으로 이미 서비스가 시작되었으며, 3GPP에서는 LPWA 네트워크 실현을 위해 Narrowband Internet-of-Things(NB-IoT)를 새롭게 소개하였다. NB-IoT는 비 3GPP 계열 LPWA 기술과의 경쟁 속에서도 빠르게 시장에 진입할 것으로 기대된다. 본고에서는 표준화가 완료된 3GPP Release 13 NB-IoT 기술과 Release 14을 목표로 표준화가 진행 중인 NB-IoT enhancement에 대해 기술한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.189-191
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• 2022

본 논문에서는 스마트항로표지용 서비스 요구사항 및 이를 실현할 수 있는 무선 통신 후보 기술을 분석한다. 이를 기준으로 기존 통신 기술과 사물 인터넷용 통신 기술로 분류하고, 요구사항 부합도를 판정하여 스마트항로표지용 최적 통신 시스템으로 AIS, LTE-M, NB-IoT 이상 3종의 통신 방신을 제안한다.

• Journal of Internet of Things and Convergence
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• v.1 no.1
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• pp.1-4
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• 2015

This paper aims to present the mathematical model to find the mean web object transfer latency in the slow-start phase of TCP congestion control mechanism, which is one of the main control techniques of Internet. Mean latency is an important service quality measure of end-user in the network. The application area of the proposed latency model is the narrowband environment including multi-hop wireless network and Internet of Things(IoT), where packet loss occurs in the slow-start phase only due to small window. The model finds the latency considering initial window size and the packet loss rate. Our model shows that for a given packet loss rate, round trip time and initial window size mainly affect the mean web object transfer latency. The proposed model can be applied to estimate the mean response time that end user requires in the IoT service applications.

• Journal of the Korea Society of Computer and Information
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• v.27 no.6
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• pp.117-122
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• 2022

In this paper, we developed a vehicle control terminal using IoT and low-power long-distance communication (NB-IoT) technology. This system collects information on the location and status of a parked vehicle, and transmits the vehicle status to the vehicle owner's terminal in real time with low power to prevent vehicle theft, and in the case of a vehicle in motion, When primary information about the vehicle, such as an impact, is collected and transmitted to the server, the server analyzes the relevant data to generate secondary information on traffic congestion, road damage, and safety accidents. By sending it, you can know the exact arrival time of the vehicle at its destination. This terminal device is an IoT gateway for a vehicle and can be connected to various wired and wireless sensors inside the vehicle. In addition, the data collected from vehicle maintenance, efficient operation, and vehicles can be usefully used in the private or public sector.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.9
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• pp.1001-1009
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• 2016

In LTE networks, the base station transmits control information over the physical downlink control channel (PDCCH) including scheduling grants, which are used to indicate the resources that the user equipment uses to send data to the base station. Because the size of the PDCCH message and the number of the PDCCH transmissions increase in proportion to the number of user equipments, the overhead of the PDCCH may cause serious network congestion problems in the narrowband LTE (NB-LTE) system. This paper proposes the compact PDCCH information bit allocation to reduce the size of the PDCCH message and evaluates the performance of the semi-persistent scheduling (SPS) in the NB-LTE system. The simulation results show that the SPS can significantly reduce the signaling overhead of the PDCCH and therefore increase the system utilization.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.2
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• pp.135-141
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• 2019

Internet of thing becomes more active, many sensor devices are increasing. Sensors can use network wired network or use mobile communication network. From the viewpoint of the transmission rate, the mobile communication network can be roughly divided into two types of high-speed communication and low-speed communication. In the case of hundreds of millions of sensors in the mobile communication network, resources are wasted to use high-speed communication. Communication is required to reduce the transmission rate and appropriately allocate resources without wasting such resources. As the Internet of Thing has been activated, Narrowband Internet of Thing(NB-IoT), which is one of the low-power technologies in recent mobile communications, is in the spotlight from various companies. Currently, it can be seen that only NB-IoT or other low power consumption communication has the potential to be able to connect to the Internet with rapidly increasing sensor devices. In this paper, we designed and implemented a heater controller using Huawei NB-IoT communication Module, a server that collects controller information, and an application that allows default settings for devices. The main function of this system is to collect temperature and heater status and give it to the server, control the heater from the server, and set parameters for the heater to operate automatically. The system can be applied to places where wired communication is not established, such as road information, smart agriculture, and small reservoirs as well as heaters.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.9
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• pp.1026-1037
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• 2016

3rd Generation Partnership Project (3GPP) is the progressing standardization of the narrowband IoT (NB-IoT) system to support massive devices for the Internet of Things (IoT) services. The NB-IoT system uses a coverage class technique to increase the performance of the NB-IoT system while serving massive devices in very wide coverage area. A moving device can change the coverage class according to the distance or the channel state between the base station and the moving device. However, in the conventional NB-IoT standard, the performance of the NB-IoT system degrades because the coverage class is changed based on the fixed criterion. This paper proposes the coverage class adaptation schemes to increase the performance of the NB-IoT system by dynamically change the coverage class according to the location or the channel state of the device. Simulation results show that the proposed coverage class adaptation scheme decreases both the signaling overhead and the PDCCH decoding error rate in comparison with the conventional coverage class adaptation scheme in the 3GPP standard.