• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12A
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• pp.1136-1146
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• 2005

In this paper, the radiative electric field intensity due to the communication signal and conductive noise is calculated in overhead medium voltage power lines for power line communication. The input impedance is calculated by means of 2 port equivalent model of medium voltage power line network and basic transmission line theory. And then, currents is calculated by calculated input impedance and finally, the emissive electric field is calculated. The input impedance appears like a standing wave form with a fixed cycle because high reflection at the input terminal due to the characteristic impedance of medium voltage power line is very large. A calculated current and radiative electric field also appears like this form. From the measurement results, the measured results are very similar to the calculated results.

• Journal of the Optical Society of Korea
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• v.8 no.4
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• pp.149-155
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• 2004

Newly developed modal transmission-line theory(MTLT) is used to analyze rigorously the optical power distribution in grating-assisted directional couplers(GADCs) with three guiding channels. By defining a novel coupling efficiency ${\eta}$ amenable to the rigorous analytical solutions of modal transmission-line theory, we explicitly evaluate the power coupling and distribution of TM modes. The results reveal that the incident power is sensitively partitioned through three output channels in terms of such grating parameters as the grating period, the duty cycle, and the operating wavelength.

• ETRI Journal
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• v.16 no.1
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• pp.59-72
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• 1994

In this paper, a new N-way hybrid power combiner for improving the graceful degradation performance has been proposed. The proposed combiner has been configured with two dummy transmission lines per each section, where each dummy transmission line has a different characteristic impedance, of the standard combiner. Under this proposed configuration, a detailed theoretical analysis has been performed to show the general function of a power combiner. When any M amplifiers among N identical amplifiers are suffering the failure mode in a power combining circuit or system, the graceful degradation performance has been improved due to the separation of a transmission line and an internal resistor in every failed section from the proposed combiner by simultaneously operating two shorting devices. Simulation results for all the items which can be measured from all the items which can be measured from the proposed combiner with an eight-way configuration have been presented.

• Journal of Korea Multimedia Society
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• v.18 no.6
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• pp.742-752
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• 2015

The communications through the power lines are called as the PLC and this is a common name for the communication modes for the information delivery. This technology transmits the data through the power lines on which the information is stored with the form of high frequency signal. The characteristic of the frequency signal is that the signal can be separated from the power line through exclusive power line modem and transmitted to the terminal devices. In this paper, 'In-home Headcount' checking algorithm using Wi-Fi and taking above mentioned advantages is proposed, and the basic Technology for such Solitary Senior Citizen's Lonely Death monitoring system has been designed and implemented. The comparative analysis has been conducted in this paper with the test-operated and test bed-completed 'Hyosimi 119 Safety-Welfare System' which is still being tested since 2008. With the 'In-home Headcount Checking Algorithm', Wi-Fi connection/disconnection status and SSIDs of relevant Wi-Fis will be checked. We expect that our proposed method will become as the basic Technology which can prevent lonely deaths of elderly people living alone. Since the PLC technology can be normally implement all the functions used on internet anticipate that the technology could be applied to many areas to construct a new form of communication network.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.5
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• pp.345-352
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• 2004

Currently, high data rate PLC(Power Line Communications), up to 100 Mbps, which use frequency bandwidth between 2 MHz and 30 MHz is investigated very hard, and commercial PLC modem for low voltage powerline network (indoor) is coming soon into communication market. For the purpose of developing a fit communication system which has little distortion of signal and attenuation, it is surely necessary to know about channel environments of powerline. Especially, the impedance measurement of the powerline and impedance matching are very important. As is known, since medium-voltage powerline (22.9 ㎸) is still working, it is not so simple to measure the powerline impedance. In our study, a portable impedance measurement equipment is developed. It consists of coupling capacitor, a drain coil and impedance matching transformer. The equipment is easily connected to medium voltage line and impedance of power line is measured using a network analyzer. Also, measurement results are used for impedance matching of PLC signal. In fact, matching transformer with several different impedances are used. The matching transformer is connected between coupling capacitor and signal port. In this paper, the developed portable impedance measurement equipment and impedance measurement results are presented. Also impedance matching technique using matching transformers will be explained. We showed the result of the improved performance by the impedance matching.

• Journal of IKEEE
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• v.23 no.3
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• pp.777-784
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• 2019

A pre-fire awareness and automatic notification system are required because it is possible to minimize the damage if the fire situation is precisely detected after a fire occurs in a place where people are unusual or in a mountainous area. In this study, we developed a RaspberryPi-based fire recognition system using Faster-recurrent convolutional neural network (F-RCNN) and single shot multibox detector (SSD) and demonstrated a fire alarm system that works with power line communication. Image recognition was performed with a pie camera of RaspberryPi, and the detected fire image was transmitted to a monitoring PC through an inductive power line communication network. The frame rate per second (fps) for each learning model was 0.05 fps for Faster-RCNN and 1.4 fps for SSD. SSD was 28 times faster than F-RCNN.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1678-1679
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• 2007

This paper is the electric power system remote control of semiconductor plasma manufacturing equipment using PLC(power line communication). PLC is useful for economical data link but various problems and limitations are caused in using power lines for communications channel Develop of Semiconductor plasma manufactur ing equipment and remote automation technologies of tool develops day after day and standards. Also, Remote electric power control and device module control by GUIRCS(Graphic User Interface Remote Control System) of tool are monitoring in real time.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.115-118
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• 2003

In this paper, we analysed the technical characteristics of power line communications interfering marine mobile services. The various radio services including marine mobile potentially affected by unwanted radiation from telecommunication networks as PLT, VDSL, ADSL, etc. The radio spectrum is unique resource. In particular, the frequency range below 30MHz has extremely favourable propagation conditions allowing economic long range as well as low power communication radio services. The paper were as follows to identify marine mobile service that are likely to be affected by PLC and evaluate the protection needs and to investigate methods of measuring the emissions from PLC.

• The Journal of Information Technology
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• v.6 no.4
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• pp.81-91
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• 2003

This paper is concerned with the implementation of power line communication system with 9.6Kbps. This system is suitable to establish the smart home using the power line having been installed in house. In the suggested power line communication system, we use the chirp signal with a linearity and spread spectrum frequency band of 100KHz~200KHz. We had the performance experiment for the implementation system. The experiment was achieved in the pseudo load network similar to real circumstance of power line communication. As the result, the communications under the circumstance were accomplished satisfactorily. We confirmed that the suggested 9.6Kbps power line communication system with the Chirped-SS method had the performance enough to commercialize the smart home.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.10
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• pp.157-162
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• 2010

Power line communication, using 25[kV] high voltage of railway catenary, is to provide information which is real-time safety information for train operations and train workers in driving. Lots of noise were occupied in the contact wire by electrical and communication equipments. A signal attenuation was caused characteristics of the contact wire and messenger wire. For relaying communications to transmit information using the contact wire, catenary the noise and signal attenuation were investigated. And the final goal of the study was realized to transmit video information by power line communication on electric railway.