• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.14 no.1
• /
• pp.1-19
• /
• 2020

In an underlay cognitive simultaneous wireless information and power transfer (SWIPT) network, communication from secondary user (SU) to secondary destination (SD) is accomplished with decode-and-forward (DF) relays. Multiple energy-constrained relays are assumed to harvest energy from SU via power splitting (PS) protocol and complete SU secure information transmission with beamforming. Hence, physical layer security (PLS) is investigated in cognitive SWIPT network. In order to interfere with eavesdropper and improve relay's energy efficiency, a destination-assisted jamming scheme is proposed. Namely, SD transmits artificial noise (AN) to interfere with eavesdropping, while jamming signal can also provide harvested energy to relays. Beamforming vector and power splitting ratio are jointly optimized with the objective of SU secrecy capacity maximization. We solve this non-convex optimization problem via a general two-stage procedure. Firstly, we obtain the optimal beamforming vector through semi-definite relaxation (SDR) method with a fixed power splitting ratio. Secondly, the best power splitting ratio can be obtained by one-dimensional search. We provide simulation results to verify the proposed solution. Simulation results show that the scheme achieves the maximum SD secrecy rate with appropriate selection of power splitting ratio, and the proposed scheme guarantees security in cognitive SWIPT networks.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.12 no.6
• /
• pp.1035-1042
• /
• 2017

In this paper, we implement a public address system using power line communication in order to operate, extend, and expand the complicated public address devices and cables easily. Power line communication based public address system implemented consists of a public address control board and public address speaker boards which are suitable to digital streaming modulation. It can be noticed that we met satisfied results from performance measurement such as maximum audio output, audio channel response time, audio output SNR, and audio output THD+N.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.11 no.7
• /
• pp.3351-3369
• /
• 2017

In recent years, datacenters, network devices and computers have proliferated. The power consumed by information and communication technology (ICT) devices has inflated in an extraordinary manner. Green communication has emerged as a new approach to reduce and optimize power consumption in ICT sector. Many methods and protocols have been proposed and implemented to achieve green communication. Nevertheless, the increase of power consumption remains a problem. In this work, we attempt to reduce and optimize power consumption of network devices in datacenters environment utilizing software defined network (SDN) paradigm. To gain more insight of the power consumption requirements of network switches, a power measurement system is constructed to measure power consumption levels of network devices. Subsequently, we propose a duplication resolver algorithm (DRA) to power off/on switches reactively. DRA algorithm reduces the required time by switches to construct their flow tables after rebooting. To this end, DRA-based external circuit has been constructed utilizing Ethernet module and an Arduino kit to control power supplies of network devices. To facilitate our work, a testbed has been constructed utilizing Ryu SDN controller, HP2920-24G switches and Arduino kits. Our results show that DRA algorithm can reduce both the power usage and start-up time delay of network switches after failures.

• Proceedings of the IEEK Conference
• /
• 2005.11a
• /
• pp.31-34
• /
• 2005

In this paper, we proposed a MAC protocol which can be used in power line communications(PLC). In the power line communication network, the data signal cannot travel long distance because of a serious attenuation. Consequently, we need to have a number of repeaters (amplifiers) in order to recover the signal power, which causes flooding problem in the network The proposed MAC protocol uses polling concept and solves the flooding problem in the power line communication network. The proposed protocol can be applied to power line communication networks for automatic power distribution control system. A mathematical analysis has been carried out to estimate the performance of the proposed protocol.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.12 no.4
• /
• pp.426-432
• /
• 2012

A fully-integrated low power K-band radar transceiver in 130 nm CMOS process is presented. It consists of a low-noise amplifier (LNA), a down-conversion mixer, a power amplifier (PA), and a frequency synthesizer with injection locked buffer for driving mixer and PA. The receiver front-end provides a conversion gain of 19 dB. The LNA achieves a power gain of 15 dB and noise figure of 5.4 dB, and the PA has an output power of 9 dBm. The phase noise of VCO is -90 dBc/Hz at 1-MHz offset. The total dc power dissipation of the transceiver is 142 mW and the size of the chip is only $1.2{\times}1.4mm^2$.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2007.05a
• /
• pp.245-249
• /
• 2007

The tendency of lightning surge to propagate displays the difference for applicable power and equipment. However, looking into the subject equipment with the lightning surge, the lightning surge can be divided in between the two lines of power, between the power line and the ground, the power line and the PE conductor, between the neutral line and the ground and the like. In addition, in the event of the communication equipment, there exists the case of lightning surge entered from the power line in addition to the entry between the communication lines, the communication line and the ground. In this study, the tendency of propagation of lightning surge penetrated on to the subject equipment is analyzed through the empirical experiment in accordance with the ground method by using the independent ground, common ground, bypass arrester and others among the techniques for safety improvement in power lines.

• Journal of Industrial Technology
• /
• v.19
• /
• pp.81-89
• /
• 1999

We have developed a power line simulator which is one of the basic tools for the research of the power line communication and its control system. In the developed simulators, we have considered the transfer function of the power line, noises and signal attenuation characteristics. Simulator was made using the matlab tool program. We made the power line modern using the FSK chip(ST7537) and experimentalized to show the efficiency grade of simulator. We have expected that the developed simulators are very useful in the area for the power line communication research and the control system design.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.15 no.6
• /
• pp.475-484
• /
• 1990

This paper proposes a method for the implementation of a power line communication equipment using power line synchronization in a direct-sequence spread spectrum communication system. In order to implement a network using a power line as a transmission channel we have investigated the utilization of direct-sequence speread spctrum which gives such advantages as robustness against narrow-band interference and noise, and realization of multiple access. In a power line, however, complexity of synchronization makes it difficult to realize a multiple access and cost down and system simplification. The proposed technique of power line synchronization makes it possible to get cost down and system size small, and the realization of multiple communication can be achieved by the addition of address setting circuit.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.49 no.9
• /
• pp.546-553
• /
• 2000

W e have developed a power line simulator which is one of the basic tools for the research of the power line communication and its control system. In the developed simulators, we have considered the transfer function of the power line, noises and signal attenuation characteristics. Simulator was made using the matlab tool program. We made the power line modem using the FSK chip(ST7537) and experimentalized to show the efficiency grade of simulator. We have expected that the developed simulators are very useful in the area for the power line communication research and the control system design.

• Proceedings of the KIEE Conference
• /
• 2003.07d
• /
• pp.2349-2351
• /
• 2003

Over the past $2{\sim}3$ years power utilities have shown a marked change in attitude by an ever increasing interest in using relay communication features. As yet there is no accepted international standard for communication protocol in automation systems. Recent work within the UCA work group has resulted in the proposal, UCA 2.0, as the informative interface for automation systems. This proposed standard embodies the generic principles developed and used within generic protocol. This paper describes and analyses various communication protocols for automation systems in electric power companies.