• ETRI Journal
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• v.10 no.3
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• pp.157-164
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• 1988

In proportion to the increased density in electronic packaging from chip to system levels of telecommunication system, thermal management is becoming a vital subject to save the cost of the electronic product and to maintain high reliability. The key to the successful application of the thermal management technique is the capability to predict the equipment thermal behaviors in early stage of system development and product design. This paper describes the application of correlations of natural convection to TDX-10 digital switching system, which has been under the 5 year development project since 1987, in order to predict equipment temperature and thermal behaviors whihin a rack.

• International journal of advanced smart convergence
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• v.6 no.2
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• pp.16-23
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• 2017

In contemporary modern society, people are constantly exposed to many kinds of noise, such as that from machinery, aircraft, construction sites, or road traffic. Noise is considered one of the most indispensable and influential parts of human life. This study investigates the acoustic characteristics of noise transfer from external sources to the human ear. For this study, we measured and analyzed various types of noise environments, installed monitoring speakers in a semi-anechoic room, and conducted intentional noise-filled experiments. In this environment, the size of the sounds generated by use of a portable device was also measured and the SNR (signal to noise ratio) calculated to study the influence of the noise. As sound is transmitted to the ear and the human body, it affects not only auditory damage but also other parts of the body. In this paper, we propose a proper SNR for noise emitted by portable IT equipment to prevent hearing loss when IT equipment is used.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.121-124
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• 2007

This article describes a function and structure of access network equipment under BcN environment. Access network until now have constructed separately to offer voice, data service. However, simplifies network structure, function that can do traffic concentration, subscriber certification, individual charging, QoS according to service and routing is required in BcN. In this paper, compare method offering by separate system with existing access network and method that offer integrating function inside system for structure of suitable access network to BcN and search structure of access network equipment for desirable access network of hereafter. Composition of this paper is as following. In Chapter 2, establishment history and structure of access network until present. In Chaprte 3, define suitable requirement and functions to BcN. And compare structure for access net work that is new with present. Last Chapter 4, suggests direction of structure of BcN access network and concludes conclusion.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.1446-1448
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• 2004

Communication line used in the rail-road have different use from subscriber line in the public telecommunication. But, when an existing communication equipment is replaced, by applying new high-speed transfer technology, we can anticipate the increase of transmission rate and decrease of waiting time according to high-speed of communication line. cost reduction of infrastructure construction and maintenance/repair according to centralization of communication line and transmission equipment. In this study, the transmission scheme of several xDSL(Digital Subscriber Line) modems were compared and analyzed. The way of applying xDSL modem to the metal cable which is used in the JR(Japan Railroad) is analyzed. In addition, the result tested in railroad communication line was reviewed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.4
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• pp.839-843
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• 2005

In this paper, wish to improve reception performance of general receiver manufacturing maritime broadband reception amplifier that can thread easily in VHF transmit-receive equipment into downsize, light weight, low-coat. Manufactured reception amplifier expressed Characteristic that improve reception sensitive 3dBm in $140MHz\~170MHz$ frequency band. Therefore, may use communications equipment that utilize VHF wide-band more efficiently. Also, practical use degree is considered to be very high because telecommunication of good quality is available.

• International Journal of Railway
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• v.3 no.1
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• pp.34-37
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• 2010

In recent, the railway system consists of subsystems as rolling stock and infrastructures as signaling, telecommunication, power supply, overhead contact and platform screen door, etc. Furthermore, each subsystem has complicated interface so as not to understand these relationship. Consequently, to operate the railway system continuously with required safety and availability, the failure data should be corrected and analyzed systematically during operation. To achieve this object effectively, this paper presents the method which is evaluating the operational risk quantitatively using failure data, and selecting the critical equipment. Following this analysis, the improvement plan is established and applied to reduce the operational risk on system or equipment. From this study, the critical equipments of system could be determined and prioritized by risk analysis. Also, the effective maintenance to prevent critical failure could be implanted by this suggested methodology.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.11
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• pp.1471-1476
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• 2018

In this paper, a high-gain antenna for satellite communication is proposed. The proposed antenna consists of septum polarizer, circular waveguide, Hat-feed structure that has a high-gain and efficiency. Especially, it is smaller and lighter than the conventional satellite communication antennas by applying a hat-feed structure. The measured results show that received gain of proposed antenna is better than 29.9 dBi and transmitted gain of proposed antenna is better than 30.5 dBi. The co-polarized and cross-polarized radiation patterns comply with ITU-RR Ap.8 and ITU-R S.731-1 that are recommended by International Telecommunication Union. The designed high-gain antenna for satellite communication is expected to be used for OTM and airborne satellite systems.

• Journal of Satellite, Information and Communications
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• v.8 no.4
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• pp.95-99
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• 2013

GPS service is generally being used in the navigation application such as the car navigation and the smart phone. Recently, GPS service continues to increase in the timing application such as the mobile telecommunication network, the smart grid, and the financial network. As GPS signals are sensitive to GPS jamming, it should be monitored and protected. In oder to prevent and minimize the damage caused by GPS jamming, many countries are developing and operating GPS jamming monitoring system. This paper presents the implementation and the test results of the GPS jamming equipment which provides the detection, the direction finding and the location of GPS jamming.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.11
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• pp.1564-1570
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• 2014

An electric vehicle (EV) not only receives electric power from the electric vehicle supply equipment (EVSE), but it also exchanges the information regarding charging process with the power gird through the EVSE. However, the EV and EVSE communicate using the ISO/IEC 15118 standard while the EVSE and power grid communicate using the IEC 61850 standard. Therefore, the EVSE should support both the ISO/IEC 15118 and IEC 61850 standards, and provide a data mapping function between the two communication protocols so that the EV and power grid, which support different protocols, can communicate with each other throughout the charging process. In this paper, we propose a mapping method of the EVSE, which converts the ISO/IEC 15118 data to IEC 61850 and vice versa, based on the XML schema of each protocol. The proposed method converts the data using the XSL (eXtensible Stylesheet Language) method, which defines the data mapping between two XML schemas. Our approach is more flexible and easier to maintain against changes in charging scenarios and the standards than other existing approaches such as one-to-one data mapping methods.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.287-291
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• 2008

DWDM(dense wavelength division multiplexing)-PON technology is applied to subscriber network as the same as E-PON or G-PON. And its network components consist of OLT, ONU and RN. Legacy DWDM technologies have been applied on the long-haul part of optical network due to its excessive high cost. But many researchers have successfully devised a few methods which can considerably reduce the cost of equipment. Nowadays DWDM-PON equipment's has arrived to a level having a competitive price in comparison to E-PON or G-PON on condition of giving equal bandwidth. Recently a major domestic ISP has deployed DWDM-PON equipments in one apartment complex area in the purpose of satisfying ever-increasing bandwidth demand. The ISP increased data transmission capacity from 1 G to 16G without any additional fiber deployment. In this paper we introduce roughly three technologies of implementing DWDM-PON's optic module and related optic devices. And we also describe pre-test of vendor's DWDM-PON equipment and discuss the result. Lastly we propose some of network configurations which adopt DWDM-PON technology. By adopting DWDM-PON technology ISP can greatly save the cost of deploying broadband subscriber network.