• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.291-295
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• 2022

This paper deal with the advanced thchnology of water supply line breakege detection system in singsan green city. the technology apply for construction eco oriented high-tech city to merge residant, industial, tour reasure parts for songsan green city furture direction achivement and response for a life style change of people in the city. Breakege detection system consist of smart prevention seat, pipeline breakege detection sensor, analysis software, server. etc.. Central control unit sent the data to hwa sung city water supply office by WCDMA in SKY. the data are states about water supply pipeline, Location.etc. This system maintain the long term life cycle of water supply plpeline by the prevention the leakege event through ackonwledge information of evnet occurrence locaion. and used to realtime sense method about demage information of the pipeline and prevent to brekege facilities during excavation work.

• Journal of Advanced Navigation Technology
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• v.26 no.6
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• pp.456-463
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• 2022

The SAM(Surface-to-Air Missile) systems will be operated until disposing of it after production, the necessary test and evaluation should be performed during the development stage to ensure the operational performance after deployment. As development of technologies related to the electromagnetic wave field of missile system is required, so the verification of the electromagnetic environment has become more important. Therefore it is necessary to carefully review whether there are any weaknesses through the analysis of the SAM system when establishing the test and evaluation procedure. This paper describes the general electromagnetic test procedure for SAM system and discusses the matters that need to be supplemented. Also, methods for supplementation and review results were written.

• IEMEK Journal of Embedded Systems and Applications
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• v.19 no.3
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• pp.151-158
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• 2024

Although on-device artificial intelligence (AI) has gained attention to diagnosing machine faults in real time, most previous studies did not consider the model retraining and redeployment processes that must be performed in real-world industrial environments. Our study addresses this challenge by proposing an on-device AI-based real-time machine fault diagnosis system that utilizes continual learning. Our proposed system includes a lightweight convolutional neural network (CNN) model, a continual learning algorithm, and a real-time monitoring service. First, we developed a lightweight 1D CNN model to reduce the cost of model deployment and enable real-time inference on the target edge device with limited computing resources. We then compared the performance of five continual learning algorithms with three public bearing fault datasets and selected the most effective algorithm for our system. Finally, we implemented a real-time monitoring service using an open-source data visualization framework. In the performance comparison results between continual learning algorithms, we found that the replay-based algorithms outperformed the regularization-based algorithms, and the experience replay (ER) algorithm had the best diagnostic accuracy. We further tuned the number and length of data samples used for a memory buffer of the ER algorithm to maximize its performance. We confirmed that the performance of the ER algorithm becomes higher when a longer data length is used. Consequently, the proposed system showed an accuracy of 98.7%, while only 16.5% of the previous data was stored in memory buffer. Our lightweight CNN model was also able to diagnose a fault type of one data sample within 3.76 ms on the Raspberry Pi 4B device.

• The KIPS Transactions:PartC
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• v.8C no.5
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• pp.565-572
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• 2001

Recently, due to the open architecture of the internet and wide spread of internet users, the cyber terror threatens to the network\`s weak point are tending grow. Until now, information security solutions are passive on security host and particular security system. This passive information security solution is weak from the attacks through the networks connected worldwide internet systems, and has limitation on the defense against cyber terror attacks. Therefore, network level integrated security function must be provided. In this paper, we consider technology limitations on the information security problems and its environment. Then we present the architecture and functions of policy-based information security services for network level active information security function. This paper also includes design of target system, which provide information security services. Finally, we discuss network level system deployment direction and discuss with Network Security Simulation.

• The KIPS Transactions:PartC
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• v.18C no.2
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• pp.103-110
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• 2011

Although a mobile Internet telephony service becomes popular with the rapid propagation of smart phones, its service quality management system has not been prepared enough yet. For successful settlement and deployment of the mobile Internet telephony service in future, a strict service quality management is required. The service quality management using a specific measurement equipment has limitations that real-time monitoring is impossible. In this paper, therefore, we propose a proactive service quality management system for the mobile Internet telephony service and develop a software for its implementation. The developed software is verified by comparing the measurement results from the developed software to those from the softwares commonly used, and it is proved that the developed software is quite reliable.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.5
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• pp.440-448
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• 2015

Kinetic energy(KE) rod warhead system is a new interceptor which combines advantages of existing ones. This system is less dependant on a precision guidance than direct hit type warhead and gives high penetration rates than blast fragmentation type warhead. In this paper, isotropic KE rod warhead system is introduced with detonation/deployment model. A penetration effects of the deployed rods are calculated using TATE penetration equation. Also, an engagement performance analysis method is suggested. Finally, an optimal detonation time and engagement geometry is derived by Monte-Carlo simulation in various engagement situation using the performance analysis factor.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.3B
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• pp.144-152
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• 2005

Mobile IP(MIP) and SIP have been proposed to support mobility in the wireless internet working at different layers of the protocol stack. However MIP has some problems such as triangle routing, the need of each host's home address, the overhead of tunneling and the lack of wide deployment. Thus we proposed a scheme for supporting mobility based on SIP in this research. A novel SIP system to provide a hierarchical registration has been designed according to this scheme. Our SIP system has been established by implementing JAIN technologies which follow next generation network standards to support the mobility of wireless terminal. This system successfully satisfied ITU-T recommendation.

• IEMEK Journal of Embedded Systems and Applications
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• v.7 no.4
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• pp.163-172
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• 2012

A driver assistance system is critical to improve a convenience and stability of vehicle driving. Several systems have been already commercialized such as adaptive cruise control system and forward collision warning system. Efficient vehicle detection is very important to improve such driver assistance systems. Most existing vehicle detection systems are based on a radar system, which measures distance between a host and leading (or oncoming) vehicles under various weather conditions. However, it requires high deployment cost and complexity overload when there are many vehicles. A camera based vehicle detection technique is also good alternative method because of low cost and simple implementation. In general, night time vehicle detection is more complicated than day time vehicle detection, because it is much more difficult to distinguish the vehicle's features such as outline and color under the dim environment. This paper proposes a method to detect vehicles at night time using analysis of a captured color space with reduction of reflection and other light sources in images. Four colors spaces, namely RGB, YCbCr, normalized RGB and Ruta-RGB, are compared each other and evaluated. A suboptimal threshold value is determined by Otsu algorithm and applied to extract candidates of taillights of leading vehicles. Statistical features such as mean, variance, skewness, kurtosis, and entropy are extracted from the candidate regions and used as feature vector for SVM(Support Vector Machine) classifier. According to our simulation results, the proposed statistical feature based SVM provides relatively high performances of leading vehicle detection with various distances in variable nighttime environments.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.6
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• pp.522-528
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• 2014

A UHF/VHF full-duplex communication using monopole and dipole antenna has been widely used for cube satellite applications. This kind of communication system requires a dedicated structure panel for antenna integration, which is the one of the disadvantages of the conventional communication system from the accommodation point of view considering the extremely limited volume of the cube satellite. In this study, to maximize the accommodation efficiency of the cube satellite, the commercial UHF half-duplex antenna combined with buck converter for communication modes transition has been considered in the communication system design. Its effectiveness has been verified through link budget analysis based on the antenna specifications and satellite's operation conditions. In addition, the antenna deployment mechanism for the synchronous release of multi-antennas has also been introduced.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.3
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• pp.1299-1304
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• 2014

This paper is a study for developing an agriculture automatic hose reel of mobile robot. One of the important works in farming is pesticide spraying because it is related to the growth of crops. Therefore, we develop an automatic reel hose and mobile robot. Conducting kinematic analysis of steering performance, the mobile robot is designed to move smoothly even in a small space, and that is verified by simulation. To increase supplying accuracy of the automatic hose reel, the mobile robot use detecting tension mechanism on a hose and a device for the hose deployment. We conduct performance and on-farm evaluation. This system has been maximum speed of 2.5m/s, driving accuracy of ${\pm}0.18^{\circ}$ and driving safety speed of 2m/s. The system would solve an aging population and shortage of workforce in agriculture.