• Journal of Communications and Networks
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• v.18 no.3
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• pp.340-350
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• 2016

The performance of large-scale cognitive radio (CR) networks with secondary users sustained by opportunistically harvesting radio-frequency (RF) energy from nearby primary transmissions is investigated. Using an advanced RF energy harvester, a secondary user is assumed to be able to collect ambient primary RF energy as long as it lies inside the harvesting zone of an active primary transmitter (PT). A variable power (VP) transmission mode is proposed, and an energy-based opportunistic spectrum access (OSA) strategy is considered, under which a secondary transmitter (ST) is allowed to transmit only if its harvested energy is larger than a predefined transmission threshold and it is outside the guard zones of all active PTs. The transmission probability of the STs is derived. The outage probabilities and the throughputs of the primary and the secondary networks, respectively, are characterized. Compared with prior work, the throughput can be increased by as much as 29%. The energy-based OSA strategy can be generally applied to a non-CR setup, where distributed power beacons (PBs) are deployed to power coexisting wireless signal transmitters (WSTs) in a wireless powered sensor network.

• Journal of the Korea Society for Simulation
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• v.8 no.2
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• pp.101-109
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• 1999

In a commercial facsimile network system, a simulation analysis has been performed using ARENA due to the unavailability of theoretical models. The effect of a priority is compared with that of the current FCFS rule on the arriving call blocking rate and transmission time delay. The result shows that the priority rule reduces more service time delay as the arrival rate increases. A simulation analysis procedure is proposed to select optimal in/out port ratio at various hourly arrival rates with a given multiple-place transmission requests ratio.

• Journal of Broadcast Engineering
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• v.1 no.2
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• pp.96-107
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• 1996

In case of remote image retrieval via shared network or low speed link in order to make a decision for target image problems such as transmission delay are encountered. In this paper browsing and optimization techniques are proposed for fast retrieval of Image by the multiresolution representation and progressive transmission. The proposed network model was analyzed and evaluated for system's performance improvement. Interactive user-system using several multiresolution representation has shown better performance in transmission delay minimization over the single resolution image retrieval system.

• Proceedings of the KIEE Conference
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• summer
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• pp.51-53
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• 2004

KEPCO is now promoting the overseas transmission businesses on the basis of competitive transmission technology. This paper deals with a development study on the power system network analysis in Myanmar which was performed as the first overseas transmission business of KEPCO. The aim of this study is to establish comprehensive and stable power system network plan by analyzing the current and future system in Myanmar.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.201-203
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• 2006

This paper presents a graphical windows-based software for the education and training of the transmission network use of system charge. The developed simulator consist of the main module(MMI,GUI), the power flow module(PF), the power flow tracing module(PFT) and management of usage cost DB module(UCD). Each module has a separate graphical and interactive interfacing window. To have effective education for transmission network use of system charge, the developed simulator are provided with two power system analysis methods. Input data of power system can use the format of PSS/E input data. Also calculation of power flow tracing are provided with four methods such as "Felix Wu","Modified Felix Wu", "DCLF ICRP" and "Reverse MW mile". Results of calculation for usage cost are shown on the window through the table or chart. Therefore user can confirm the detailed differences of results from each calculation method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.501-504
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• 1999

Chua's circuit is a simple electronic network which exhibits a variety of bifurcation and attractors. The circuit consists of two capacitors, an inductor, a linear resistor, and a nonlinear resistor. In this paper, a transmitter and a receiver using two identical Chua's circuits are proposed and a synchronizations of lossless transmission line are investigated. Since the synchronization of the transmission system is impossible by coupled synchronization, the drive-response synchronization theory were used. As a result, the chaos synchronization has delay characteristics in the lossless transmission system caused by the line parameters L and C.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.476-478
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• 1993

Instead of installing new communication wiring to each house in the apartment house building. the power distribution network. which is already installed in the building. can be use as communication medium. In a safty management, by adoption of power line communication system, at remote we can monitor safty related sensors such as fire, gas leakage, burglar intrusion and emergency call which are located at each house. From this viewpoint, we developed security monitoring system for apartment house building using power lines. Security monitoring system consists of Power Line Communication-Sub Controller (PLC-SC). Power Line Communication-Main Controller (PLC-MC) and Management System (MS). Between a PLC-MC and a PLC-SC, the transmission rate is 1200 bps in power lines and modulation technique is frequency shirt keying (FSK). In between a PLC-MC and a MS, the transmission rate is 1200 bps in communication line (RS-485). As a result of this research. transmission loss is 0.1dB per meter of intrabuilding distribution network. Transmission can be reach in 250 meters. So it is enough to communicate for security monitoring system in apartment house building.

• Journal of Electrical Engineering and Technology
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• v.2 no.4
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• pp.494-499
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• 2007

In this paper, we have investigated how transmission network constraints can be modeled in an electricity market equilibrium model. Under Cournot competition assumption, a game model is set up considering transmission line capacity constraints. Based on locational marginal pricing principle, market clearing is formulated as a total consumers# benefit maximization problem, and then converted to a conventional optimal power flow (OPF) formulation with a linearized transmission model. Using market clearing formulation, best response analysis is formulated and, finally, Nash equilibrium is formulated. In order for illustration, a numerical study for a four node system with two generating firms and two loads are presented.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.513-515
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• 1995

Based on the concept of Load Supplying Capability of a transmission network, we provides an information concerning network adequacy. In particular this paper describes an algorithm regarding load supplying margin of transmission networks. And a different growth rate is assigned to each load point so that various demand characteristics can be taken into consideration at respective locations. In addition to this, in this paper, both generation and transmission equipment will be considered in determining the system capability. A 10 bus model system is used to demonstrate the capability of the proposed algorithm.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.99-104
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• 2014

In this paper, the authors propose a multi-transmission mechanism of heterogeneous network environment which is applicable to the SMART screen services over wire and wireless convergence network. This paper presents study results including a SMART screen handover algorithm among multiple collaborative devices under wire and wireless convergence and heterogeneous network environment, and a service operation and management system and a NAS system providing SMART services of AV streaming and contents files. These validate implementation feasibility of a call processing engine for seamless SMART screen collaborative services, AV streaming services and SMART screen collaborative services supporting mobility management and multiple users/multiple streams.