• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1225-1228
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• 1996

This paper describes the application area of the multimedia conference system for the electric power system operation. A variety of multimedia systems which are to be installed in the existing information communication network of KEPCO are introduced.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.628-629
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• 2012

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.11
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• pp.1159-1166
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• 2014

In this paper, a resource management scheme for enhancing the network connectivity and reliability in wireless USB system is proposed. Wireless USB protocol is suitable for the application that supports the real-time multimedia service in Ship Area Network since it supports high speed data transfer. However, the device's mobility is caused the dramatic change of link state and network topology, and is occurred the degradation of network performance. Therefore, a resource management scheme for wireless USB system is proposed in this paper. The proposed technique can intelligently treat the change of link state, and solve the degradation of network performance. The simulation results show that proposed protocol can enhance the throughput and delay performance by selecting relay device with better link state.

• Journal of the Korea Society for Simulation
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• v.15 no.3
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• pp.87-91
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• 2006

With the growth of the internet, the number of wireless internet users has increased continuously up to date. However, mobile communications could not support high speed transmission rate with cheap communication fee and wireless LAN has problems in providing terminal mobility and wide area connectivity, respectively. So the WMAN standard has been newly designed to make up for these limits. The initial 802.16 specification effectively offers a solution for providing fixed users with high speed wireless communication but it does not offer terminal mobility. So the 802.16d and 802.16e have been developed as the next generation solution that can support various PHY layer (SC, SCa, OFDM, OFDMA) and offer the terminal mobility. In this paper, we propose an effective uplink scheduling algorithm for VoIP with using UGS, and we show that our proposed algorithm is superior in view of average delay and management of uplink bandwidth to conventional rtPS algorithm and the scheme in reference, with using NS-2 network simulator.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.12
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• pp.1659-1665
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• 2019

In this paper, a novel design of a compact printed monopole antenna for wireless local area network (WLAN) applications is investigated. The radiator with a patch of different line width and step-shaped ground planes is used to reduce the antenna size. The size of the antenna is 16 × 17 × 1 ㎣ and is fabricated with a photolithography technique. The simulated and measured results agree well. The resonant frequency of the investigated antenna is about 5.2 GHz and can cover an impedance bandwidth of 1 GHz for the measurement result. In addition, we presented the measured radiation pattern, presented the gain and efficiency measured in the required WLAN 5 GHz frequency band (5.15-5.825 GHz), and confirmed that it can be used as a 5 GHz band WLAN antenna. The investigated antenna has a small size, light weight, low cost, omni-directional radiation pattern, high gain, and high efficiency.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.5
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• pp.1540-1560
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• 2022

Latest technological innovation in the development of compact lower power radios has led to the explosion of Internet of Things. With Wi-Fi, Zigbee and other physical layer protocols offering short coverage area there was a need for a RF protocol that had a larger coverage area with low power consumption. LoRa offers Long Range with lower power consumption. LoRa offers point to point and point to multipoint connections. with Single hop communication in place the need for routing protocols are eliminated. LoRa Wide Area Network stack can accommodate thousands of nodes under a single LoRa gateway with a single hop communication between the end nodes and LoRaWAN gateway. This paper takes an experimental approach to analyze the basic physical layer parameters of LoRa and the practical coverage offered by a LoRaWAN under highly dense urban conditions with variable topography. The insights gained from the practical deployment of the LoRaWAN network, and the subsequent performance analysis is used to design a novel public utility monitoring platform. The second half of the papers is designing a robust platform to integrate both existing wired sensor water meters, current and future generation wireless water meters. The Common Automated Metering Platform is designed to integrate both wired sensors and wireless (LoRaWAN and Wi-Fi) supported water meters. This integrated platform reduces the number of nodes under each LoRaWAN gateway and thus improves the scalability of the network. This architecture is currently designed to accommodate one utility application but can be modified to integrate multi-utility applications.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.453-456
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• 2007

In this paper, we describes a design of Wireless Mesh Network based middleware that applied into USN(Ubiquitous Sensor Networks). WMN based middleware is a technique which links data between widely distributed sensor devices and WMN for context-awareness. The use of WMN base middleware in this paper makes possible communication on insufficiently network constructed area by use of WMN. WMN based middleware also anaylze events comprehensively that originated from specific sensor device. Based on the result from analyzed data with predetermined value WMN based middleware will given an order to designated actuator devices. Middleware operate each function of sensor network management and application service separately.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.6
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• pp.55-61
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• 2008

In this paper, we proposed a multi-agent based healthcare system (MAHS) which is the combination of medical sensor module and wireless communication technology. This MAHS provides wide services to mobile telemedicine, patient monitoring, emergency management, doctor's diagnosis and prescription, patients and doctors, information exchange between hospital workers in a long distance. Also, MAHS is connected to Body Area Network (BAN) and a doctor and hospital workers. In addition, we designed and implemented extended JADE based MAHS that reduces hospital server's burden. Agents gather, integrate, and deliver the collected patient's information from sensor, and provide presentation in healthcare environment. Proposed MAHS has advantage that can handle urgent situation in the far away area from hospital like Islands through PDA and mobile device. In addition, by monitoring condition of patient (old man) in a real time base, it shortens time and expense and supports medical service efficiently.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.12
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• pp.1644-1649
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• 2019

With the rapid development of mobile communication systems, various mobile convergence services are appearing and data traffic is exploding accordingly. Because the number of base stations to support these surging devices is also increasing, from a network provider's point of view, reducing energy consumption through these mobile communication networks is one of the most important issues. Therefore, in this paper, we apply the DBSCAN (density-based spatial clustering of applications with noise) algorithm, one of the representative user-density based clustering algorithms, in order to extract the dense area with user density and apply the thinning process to each extracted sub-network to efficiently control the mode of the base stations. Extensive simulations show that the proposed algorithm has better performance results than the conventional algorithms with respect to area throughput and energy efficiency.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1984.10a
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• pp.7-10
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• 1984

In this paper, the advantages of buffer insertion access method in comparison with other access methods to local area networks are analyzed. Sending and Receiving protocols in a data link layer are designed by a software method, We have derived both qeueing delays and the response time for the performance model that is proposed in this paper, and using the computer simulation, analyzed the performance for the proposed model in terms of the throughput rate- response time characteristrics. Based on the proposed model, the hardware design is implemented.