• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.12 no.6
• /
• pp.931-939
• /
• 2001

The slot coupling characteristics was analysed in a radial-line slot antenna for its design. The previously proposed waveguide model with a periodic boundary condition on its narrow walls and periodically arranged slots on its wide wall was used. The magnetic field integral equation and two dyadic Green\`s functions for respective regions was derived and the method of moments was used. To maximize the efficiency of numerical analysis and to extract singularities, two different kinds of basis functions, the entire domain basis function and the sub-domain one, are used. In addition, the Ewald sum technique for the rectangular waveguide and the Shanks transform for the half space were used to accelerate the computation of the slowly convergent potential Green\`s functions. Simulation results expressed the effects of the various design parameters on the slot coupling.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.22 no.10
• /
• pp.870-878
• /
• 2009

The large increase in the use of electricity has resulted in an ever-growing electric power demand. It has created the need for the construction of power transmission facility located close to the load centers and it also has to require wide right-of-way and large lots, that are not always available, for especially the installation of the towers. The difficulties in acquiring right-of-way have put pressure on energy companies to either upgrade a line on an existing right-of-way to higher voltage or build a new line on a narrow right-of-way. This paper presents the design of a compact tower with polymer Insulation arm, in order to reduce the separation between phases. the compact tower can be built on a narrow right-of-way. the compact tower can be designed based on 345 kV Tower regarding electrical clearances and right of way, therefore the conventional 154 kV Tower can be upgrading transmission line voltages have moved to 345 kV levels.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38A no.10
• /
• pp.874-884
• /
• 2013

This paper presents in details channel and noise characteristics over narrow bands below 500kHz based on the field tests over underground low voltage(LV) power lines in residential areas in Korean grid. We show that the channel characteristics of narrowband signals over underground LV power line are decent. We first describe methodology of channel characteristic measurements including channel frequency response, noise, and line impedance, and obtain channel characteristics over the underground LV lines in the residential areas. Also based on the measurement results, we adopt the IEEE P1901.2 standard on the FCC High band, and bring up narrow band power line communication network.

• Proceedings of the KSRS Conference
• /
• 1999.11a
• /
• pp.310-315
• /
• 1999

We extracted narrow open water streams from JERS-1 SAR images of the Amazon rain forest. The extracted range of these streams were almost comparable to a high level extraction of the same streams from near-IR images of JERS-1 VNIR data notwithstanding that these features in SAR images show the strong dependence of the observation angle. Large water bodies are relatively easy to extract from JERS-1 SAR images, as they tend to appear as very dark areas; but streams whose width is nearly equal to or less than the spatial resolution no longer appear as very dark features. By using strong scatterers distributed sparsely along the radar facing sides of the streams, we can successfully estimate approximate ranges of waterways and then extract relatively dark line-like features within these ranges.

• The Bulletin of The Korean Astronomical Society
• /
• v.43 no.1
• /
• pp.49.2-49.2
• /
• 2018

Flux calibration for narrow band photometric data gives us an opportunity to get a line flux of extended targets. We developed flux calibration processes for narrow band photometry using broad band filters as a continuum indicator. We derived parameters for color correction and zero point correction including color terms. Applying our method, we successfully subtracted continuum emissions and calibrated the emission lines from an FU Ori type object, V960 Mon.

• Journal of Institute of Control, Robotics and Systems
• /
• v.12 no.10
• /
• pp.1050-1055
• /
• 2006

Since the muiltipath signal arrives at the GPS receiver later than the line-of-sight signal, the multipath signal makes the shape of the correlation function asymmetric. This paper proposes a multipath mitigation method through asymmetry estimation of the correlation function, in which multiple correlators are utilized. The asymmetry is estimated from correlation values of correlators which have different chip spacings. Based on the estimated asymmetry, the correlation function is modified in order to get a better code tracking performance. Even through the proposed method uses multiple correlators including the narrow correlator, the acquisition performance is not degraded since the number of search cell of the narrow correlator part can be reduced in the algorithm of the proposed method. The simulation results show that the proposed method gives better performance than the generic correlator in multipath environment.

• 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.

• Proceedings of the KIPE Conference
• /
• 1997.07a
• /
• pp.211-215
• /
• 1997

Localized communication networks for office automation, security monitoring, environmental management of buildings, computer communications, and other applications enjoy every increasing demand. This paper proposes a direct sequence spread spectrum communication system for use in power line data transmission. Advantages of power distribution circuits include reasonably universal coverage and easy access vis a standard wall plug. Disadvantages include limited communication bandwidth, relatively high noise levels, and varying levels of impedance, noise, and attenuation. Spread spectrum signalling provides immunity to narrow-band signal impairments and multiplexing capability. Our prototype power line communication module supports completely physical and data link layers based on the international standard ISO 10368 for reliable high-speed power line communication system. Moreover it provides useful functions to compose a plant monitoring and control system. All the circuits of the communication module are included in one compact circuit. Thus a functional communication system for the power line plant monitoring and control is implemented.

• Asian Journal of Turfgrass Science
• /
• v.13 no.1
• /
• pp.29-36
• /
• 1999

This study was conducted to make the utmost use of the good traits and to improve the poor traits of zoysiagrass through the production technology for mixed lines sod in addition to breeding. Mixed lines sod was produced by mixing broad or middle leaf line with narrow leaf line by volume, a ratio of 1 to 2. The mixed lines sod of zoysiagrass was superior to the single ling sod, which is used commonly, for the establishment rate, coverage rate, shoot density, texture, leaf color, dormancy period cnd color, and visual quality.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.15 no.11
• /
• pp.1100-1107
• /
• 2004

In this paper, a new design method fur tapped coupled-line filters has been developed. The design equations for this tapped-line filter have been obtained using a new equivalent circuit model of tapped lines. These tapped-lines replace input/output coupled lines of the conventional edge coupled-line filters, which tend to have very narrow line gaps(few mils). Therefore, tapped coupled-line filters tend to be less sensitive to filter fabrication tolerances and to be easily fabricated using milling tools. The new filter design algorithm allows very accurate filter design for frequencies up to 20 GHz and bandwidth less than 20 %.