• Annual Conference of KIPS
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• 2011.04a
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• pp.568-571
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• 2011

센서네트워크에서 가장 기본적이고 중요한 기능 중 하나는 주변정보를 수집하고 수집한 정보를 취합하는 것이다. 하지만 정보 취합 과정에서 특정 경로를 자주 이용하게 되면, 해당 경로상의 노드들에게 에너지 소비가 집중되어 네트워크가 일찍 단절 될 수 있다. 따라서 다양한 라우팅 경로를 갖고, 모든 노드의 부하를 균등하게 분산하여 네트워크 라이프타임을 늘리는 것이 중요하다. 그간, 여러 논문에서 리니어프로그래밍을 통해 각 노드의 부하를 균등하게 분산하기 위한 연구들이 활발히 이루어 졌다. 하지만 기존 연구들에서는 무선환경에서의 충돌, 감쇄 등으로 인한 전송 실패와 재전송에 드는 에너지측면을 제대로 반영하지 못하였다. 본 논문에서는 이러한 무선 네트워크 환경에서, 노드 간 링크퀄리티를 반영하여 재전송에 드는 비용까지 고려된, 정교한 부하 균등 분산 기법을 소개한다. 링크퀄리티를 고려하였을 때, 그렇지 않았을 때에 비해 에너지 측면과 전송 지연 측면에서 최대 100%를 상회하는 성능향상 결과를 보인다.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.3975-3984
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• 2022

Distributed control system architecture is adopted for I&C systems of Prototype Fast Breeder Reactor, where the geographically distributed control systems are connected to centralized servers & display stations via switched Ethernet networks. TCP/IP communication plays a significant role in the successful operations of this architecture. The communication tasks at control nodes are taken care by TCP/IP offload modules; local area switched network is realized using layer-2/3 switches, which are finally connected to network interfaces of centralized servers & display stations. Safety, security, reliability, and fault tolerance of control systems used for safety-related applications of nuclear power plants is ensured by indigenous design and qualification as per guidelines laid down by regulatory authorities. In the case of commercially available components, appropriate suitability analysis is required for getting the operation clearances from regulatory authorities. This paper details the proposed approach for the suitability analysis of TCP/IP communication nodes, including control systems at the field, network switches, and servers/display stations. Development of test platform using commercially available tools and diagnostics software engineered for control nodes/display stations are described. Each TCP link behavior with impaired packets and multiple traffic loads is described, followed by benchmarking of the network switch's routing characteristics and security features.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.6
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• pp.482-490
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• 2023

With the advent of the Fourth Industrial Revolution, many companies are developing Smart Ships to enable autonomous navigation, unmanned operation, and cost-effective shipping. In order to facilitate the operation of these Smart Ships, significant emphasis is being placed on improving external communication capabilities and developing autonomous navigation systems. Moreover, unmanned ship operation necessitates replacing of all visually observed conditions with sensors, leading to an inevitable increase in the number of sensors and actuators compared to traditional methods. However, in South Korea, the communication network for sensors and actuators primarily relies on the conventional 1:1 hardwired wiring, with the use of higher-level communication networks when necessary. Therefore, in this paper, we introduce the AS-Interface protocol, which is used for monitoring and controlling sensors and actuators, with the expectation that it will greatly contribute to the development of future Smart Ships by reducing production time, costs, and maintenance duration.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1259-1268
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• 2023

This study proposes a throttle and steering control technology using visual sensors based on deep learning's convolutional and recurrent neural networks. It collects camera image and control value data while driving a training track in clockwise and counterclockwise directions, and generates a model to predict throttle and steering through data sampling and preprocessing for efficient learning. Afterward, the model was validated on a test track in a different environment that was not used for training to find the optimal model and compare it with a CNN (Convolutional Neural Network). As a result, we found that the proposed deep learning model has excellent performance.

• International Journal of Computer Science & Network Security
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• v.24 no.4
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• pp.141-146
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• 2024

A local area network (LAN) is a computer network within a small geographical area such as a home, school, computer laboratory, office building or group of buildings. A LAN is composed of interconnected workstations and personal computers which are each capable of accessing and sharing data and devices, such as printers, scanners and data storage devices, anywhere on the LAN. LANs are characterized by higher communication and data transfer rates and the lack of any need for leased communication lines. Communication between remote parties can be achieved through a process called Networking, involving the connection of computers, media and networking devices. When we talk about networks, we need to keep in mind three concepts, distributed processing, network criteria and network structure. The purpose of this Network is to design a Local Area Network (LAN) for a BAEC (Bangladesh Atomic Energy Commission) Head Quarter and implement security measures to protect network resources and system services. To do so, we will deal with the physical and logical design of a LAN. The goal of this Network is to examine of the Local Area Network set up for a BAEC HQ and build a secure LAN system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.6
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• pp.1462-1477
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• 2024

With the evolving complexity of connected vehicle features, the volume and diversity of data generated during driving continue to escalate. Enabling data sharing among interconnected vehicles holds promise for improving users' driving experiences and alleviating traffic congestion. Yet, the unintentional disclosure of users' private information through data sharing poses a risk, potentially compromising the interests of vehicle users and, in certain cases, endangering driving safety. Federated learning (FL) is a newly emerged distributed machine learning paradigm, which is expected to play a prominent role for privacy-preserving learning in autonomous vehicles. While FL holds significant potential to enhance the architecture of the Internet of Vehicles (IoV), the dynamic mobility of vehicles poses a considerable challenge to integrating FL with vehicular networks. In this paper, a novel clustered FL framework is proposed which is efficient for reducing communication and protecting data privacy. By assessing the similarity among feature vectors, vehicles are categorized into distinct clusters. An optimal vehicle is elected as the cluster head, which enhances the efficiency of personalized data processing and model training while reducing communication overhead. Simultaneously, the Local Differential Privacy (LDP) mechanism is incorporated during local training to safeguard vehicle privacy. The simulation results obtained from the 20newsgroups dataset and the MNIST dataset validate the effectiveness of the proposed scheme, indicating that the proposed scheme can ensure data privacy effectively while reducing communication overhead.

• Journal of the Korea Society of Computer and Information
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• v.25 no.11
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• pp.105-114
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• 2020

In this paper, we address security issues in 5G non-public networks for industrial applications. In contrast to public networks that offer mobile network services to the general public, 5G non-public networks provide 5G network services to a clearly defined user organization or groups of organizations, and they are deployed on the organization's defined premises, such as a campus or a factory. The main goal of this paper is to derive security threats and potential security requirements in the case that 5G non-public networks are built for discrete and process industries according to the four deployment models of 5G-ACIA (5G Alliance for Connected Industries and Automation). In order to clarify the scope of this paper, we express the security toolbox to be applied to 5G non-public networks in the form of the defense in depth concept. Security issues related to general 5G mobile communication services are not within the scope of this paper. We then derive the security issues to consider when applying the 5G-ACIA deployment models to the industrial domain. The security issues are divided into three categories, and they are described in the order of overview, security threats, and potential security requirements.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.611-615
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• 2008

The international society under the internet technology have been declining boundaries of the global economy. After this step, a social revolution will be happen from the ubiquitous technology which fives objects intelligence to serve people. And then it is expected that every part of a city competitive power is defined by both in qualify and in quantify of the ubiquitous information unit in the future. On this score, now each nation is trying to set relative services and broadband networks to lead the ubiquitous industry. Therefore this paper analyzed about the progress and prospect of a local U-city plan in our nation Especially we propose a new city development model which use U-city and self-communication network to Improve a city competitive power.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.6B
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• pp.358-366
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• 2007

Recently, FCC(Federal Communications Commission) has considered for that unlicensed device leases licensed devices' channel to overcome shortage of communication channels. Therefore, IEEE 802.22 WRAN(Wireless Regional Area Networks) working group progresses CR (Cognitive Radio) technique that is able to sense and adopt void channels that are not being occupied by the licensed devices. Channel selection is of the utmost importance because it can affect the whole system performance in CR network. Thus, we propose a policy-based dynamic channel selection architecture for cognitive radio network to achieve an efficient communication. We propose three kinds of method for channel selection; the first one is weighted channel selection, the second one is sequential channel selection, and the last one is combined channel selection. We can obtain the optimum channel list and allocates channels dynamically using the proposed protocol.

• The Transactions of the Korea Information Processing Society
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• v.5 no.11
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• pp.2763-2775
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• 1998

In mobile computing environments, to efficiently use the narrow bandwidth of wireless networks a mobile host caches the data that are frequently accessed. But, because the cached data can be inconsistent with the data n a server due to the host mobility and the disconnection from a server, the usefullness of cached data may be losted. The traditional methods emphasize on the cache consistency and assume that broadcasting times are synchronized at all mobile supprot stations. In this paper, we propose a strategy to maintain cache consistency, which resolves the problems that be caused by the migration of mobile host. The proposed strategy has asynchronous broadcasting time and reduces the communication overhead caused by the synchronization. Also, by preventing the unnecessary messages transmitting from the mobile support station to a mobile host, this strategy can reduce the communication cost and use the narrow bandwidth of wireless networks efficiently.