• Journal of Korea Society of Industrial Information Systems
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• v.6 no.1
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• pp.56-60
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• 2001

An authentication protocol for wireless mobile communication systems is proposed. The protocol employs the keyed hash function to provide mutual authentication and session key distribution. This makes the low computation power of mobile stations. To provide the security architecture with minimal assumption about the security of intermediate transport networks, this protocol has no assumptions about the security of the intermediate, fixed networks.

• Wind and Structures
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• v.7 no.5
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• pp.345-357
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• 2004

In the 1990s, four strong typhoons hit the Kyushu area of Japan and inflicted severe damage on power transmission facilities, houses, and so on. Maximum gust speeds exceeding 60 m/s were recorded in central Kyushu. Although the wind speeds were very high, the gust factors were over 2.0. No meteorological stations are located in mountainous areas, creating a deficiency of meteorological station data in the area where the towers were damaged. Since 1995 the authors have operated a network for wind measurement, NeWMeK, that measures wind speed and direction, covering these mountainous areas, segmenting the Kyushu area into high density arrays. Maximum gusts exceeding 70 m/s were measured at several NeWMeK sites when Typhoon Bart (1999) approached. The gust factors varied widely in southerly winds. The mean wind speeds increased due to effects of the local terrain, thus further increasing gust speeds.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.2
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• pp.39-50
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• 2002

Several pre-processing techniques for earthquake data from earthquake monitoring institutes in Korea including Korea Electric Power Research Institute are thoroughly reviewed. Among these techniques for removing an instrumental response, removing the non-causal ringing distortion by FIR filter, checking calibration status of seismic stations, and minimizing the window effect are introduced and applied to real data. It is also recommended that analysts evaluate S/N ratio in the frequency domain and consider the possibility of using the saturated earthquake data.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.291-293
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• 2003

Energy markets of the Northeast Asia countries and in particular South Korea are perspective enough from the standpoint of export of energy resources from Russia. South Korea Power System has been rapidly growing. However, recently it has been confronted with difficulties in regard to constructing new Power Stations and especially Hydro Power Plants. Therefore it is mutually beneficial to build electric tie to South Korea in order to use highly effective Power of Northeast Asia. In this paper, we describe the maximum available transmission power through interconnected line without loss of stability in power system. For this simulation, the AC transmission system is assumed appropriate for this preliminary study. The transmission system will pass through territory of North Korea and connect to 765 kV Network near Seoul with long distance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.2
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• pp.459-467
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• 2017

An urban railway power substation consists of three thyristor dual converters. Two converters are connected to up and down trolley line to supply the electric energy or feed the regenerative energy back to the distribution. When the two converters break down, the remaining converter is used in an emergency. One thyristor dual converter system (TDCS) manages the energy of two or three railway stations. If the TDCS fails, the trains stop operating. To solve the problem, this paper proposes the three parallel operation control algorithm of thyristor dual converter system using the emergency converter. The broken TDCS can be replaced by the emergency converter in other TDCS. The effectiveness of this proposed control is verified by simulation.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1646-1651
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• 2008

Due to the complaints on the emission gases from diesel locomotives, the diesel locomotives are replaced by electric locomotives, resulting in the decrease of diesel locomotives in Korea. However, the emission gases from diesel locomotives have become serious environmental concern at stations and car depots. In this study, a diesel particluate filter (DPF) for diesel locomotive was developed in order to reduce the emission gases. The concentration of nano particulate matters before and after the DPF was analyzed using a SMPS (Scanning mobility particle sizer) and MOUDI (Micro orifice uniform deposited impactor) to evaluate the performance of DPF in particulate matters removal.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.2005-2013
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• 2008

Urban transit is a large scaled complex system which combines rolling stocks, power supply, signal communications, tracks & stations etc. KRRI develops nine key devices since July, 2007 as a part of the second phase of project on the standardization of urban rail transit system, which include information-communication system, station facilities, AC-DC current electric power system in urban transit. We promote the project under two directions, i.e. user-customer oriented standardization and strategic standardization for leading technologies in urban transit. In this paper, we present development plan of these key systems in view of system life cycle based on system engineering standards KSX ISO/IEC 15288 which supplies the common fundamental frame to describe the life cycle of artificial systems. System engineering process of KSX ISO/IEC 15288 are helpful to efficiently develop those key devices, although it is difficult to apply the standard identically to the key devices with the varieties and characteristics.

• Journal of Biomedical Engineering Research
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• v.16 no.2
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• pp.191-200
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• 1995

Although air, water, and noise pollutions have been widely recognized, electromagnetic forces (EMF) hazard has been rarely recognized as a pollution and very little studies has been done in this country. Thus, in this study electromagnetic forces radiated by various home appliances, office machines, and communication equipments were measured and so were several places radiating strong EMF such as subway stations and electric substations. Among the home appliances microwave oven radiates lots of magnetic field and microwaves, and electric mattress does strong magnetic field. In video game room strong magnetic and considerable electric fields were measured. It was observed strong magnetic field inside of electric powered train and very strong magnetic and electric fields on some platforms. Hand-phone and car-phone radiate very hazardous level of microwaves to brain and that they rapidly come into wide use. In this study data base for various electric machines and places radiating strong EMFs were constructed and could be used for future epidemiological studies.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.1
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• pp.213-218
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• 2017

High-voltage power systems operate in order to generate and transmit electric power at power stations. Compared to low-power systems, high-power systems are complex in structure, large-scale, and expensive. When high-power cable accidents occur, most facilities are incapacitated-including low-power systems-causing huge economic losses. Great care must therefore be taken in designing, installing and managing power systems. Although dependent on installation circumstances and usage conditions, in some cases the cross-sectional areas of cables fall short of the critical area due to the expansion of and improper design and installation of power facilities. In this situation, the exceeded ampacity (allowable current) above the critical value caused by the operating current initiates the deterioration processes of power cables. In order to systematically monitor power cables operating at power stations, we have developed the first device of its kind in Korea. In this paper, we present the analyzed characteristics of expected temperatures of cables based on the load current of high-voltage cables operating at Korean Western Power Co. Ltd. We can predict the lifetime of cables by analyzing the temperature obtained from our device.

• Journal of the Korean Solar Energy Society
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• v.40 no.5
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• pp.13-22
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• 2020

Day ahead forecast is necessary for the electricity market to stabilize the electricity penetration. Numerical weather prediction is usually employed to produce the solar irradiance as well as electric power forecast for longer than 12 hours forecast horizon. Korea Meteorological Administration operates the UM-LDAPS model to produce the 36 hours forecast of hourly total irradiance 4 times a day. This study interpolates the hourly total irradiance into 15 minute instantaneous irradiance and then compare them with observed solar irradiance at four ground stations at 1 minute resolution. Numerical weather prediction model employed here was produced at 00 UTC or 18 UTC from January to December, 2018. To compare the statistical model for the forecast horizon less than 3 hours, smart persistent model is used as a reference model. Relative root mean square error of 15 minute instantaneous irradiance are averaged over all ground stations as being 18.4% and 19.6% initialized at 18 and 00 UTC, respectively. Numerical weather prediction is better than smart persistent model at 1 hour after simulation began.