• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1165-1168
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• 2005

We review discharge characteristics of fluorescent lamps having noncircular cross sections. The developmental and theoretical history of noncircular cross-section lamps is summarized chronologically. In particular, discharge characteristics of noncircular cross-section lamps will be summarized and analyzed including plasma contraction, electron temperature, and ambipolar diffusion loss, which might give us some insights into the way to develop more efficient and uniform flat fluorescent lamps, which have recently arisen as a new light source of large-size backlight units for LCD TV applications.

• Publications of The Korean Astronomical Society
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• v.7 no.1
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• pp.79-87
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• 1992

New and improved data on the gravitational lens systems discovered so far are compared with the theoretical predictions of Gott, Park, and Lee (1989, GPL). Systems lensed by a single galaxy, compatible with assumptions of GPL, support flat or near-flat geometry for the universe. But the statistical uncertainty is too large to draw any definite conclusion. We need more lens systems. Also, the probability of multiple image lensing and mean separation of the images averaged over the source distribution are calculated for various cosmological models. Multiple-image lens systems and radio ring systems are compared with the predictions. Although the data reject exotic cosmological models, it cannot discriminate among conventional Friedmann models yet.

• Journal of the Speleological Society of Korea
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• no.70
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• pp.51-54
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• 2006

We should understand the wetlands in the environment not only large famous but also very small wetlands. Wetlands have been understood the habitat of waterfowls and the treasure house of ecology. But All wetlands must be cognized how to be wetlands and be valuable as environment. There are many small and nonfamous wetlands in our country. They are not understood as wetlands. They are known as leaved estate, so thought as developed economically. Many leaved small nonfamous wetlands supply various good things. Most of all, they are water service and maintain of climate. These are served the source of sustenance of earth environment and ecology. They must get supported and maintained. Therefore The paradigm is shifted on the wetlands.

• Proceedings of the Petrological Society of Korea Conference
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• 2001.06a
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• pp.75-75
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• 2001

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.110-116
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• 2000

Aircraft noise is one of the main causes of environmental impact. It is more serious than any other noise nuisance. It has become an increasing source of annoyance to the large number of people who live in communities near airports. This paper demonstrates the prediction of aircraft noise using Integrated Noise Model (INM) 5.1 developed by U.S. FAA and aircraft noise contour map near airports.

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.307-310
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• 2002

A design for the input filter and the output filter of a single-phase UPS system is proposed. And also, this paper describes a reduction of the DC voltage ripple of a single-phase UPS. The input power of proposed UPS fluctuates with twice frequency of the utility source, which causes DC voltage fluctuation. The reduction of the DC voltage fluctuation requires a large DC link capacitor. The proposed method uses a LC series resonant filter paralleled with a conventional smoothing capacitor. The effectiveness of the proposed method was confirmed by simulation results.

• Korean Journal of English Language and Linguistics
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• v.1 no.3
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• pp.369-386
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• 2001

This paper will show that traditional approaches to the derivation of different negative words have been of an essentially hypothetical nature, based on either linguists' intuitions or rather scant evidence, and that native-speaker dictionary entries show meaning potentials (rather than meanings) which are in fact linguistic and cognitive prototypes. The purpose of this paper is to demonstrate that using a large corpus of natural language can provide better answers to questions about word-formation (i.e., with particular reference to negative prefixation) than any other source of information.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.8 no.1
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• pp.57-66
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• 2000

Benefit-cost analysis is one of key elements of feasibility study on a large scale investment for transportation infrastructure improvements. Benefit-cost analysis requires measuring expected benefits after the investment is completed. Reduction of delays is the major source for the benefit among other measurable benefits. Measurement methods for delays reduction have been reviewed and two methods were recommended for passenger delay and aircraft operation delay. Using these method, the effects of Cheju International Airport Improvement Projects were evaluated.

• Journal of Applied Reliability
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• v.1 no.2
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• pp.139-148
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• 2001

We are concerned in the estimation of lifetime distribution of a component having a few observed failure data and we demonstrate that we can use the maximum likelihood estimation utilizing the censored data when the number of components in use is quite large. Weibull distribution is assumed for the lifetime and a simple estimation procedure is introduced. We also propose the method of determining the optimal number of spares required for a specified period without introducing cost functions. The proposed methods are applied to the photon stop and the water-cooled flange which are major components in Pohang Light Source.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05b
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• pp.169-173
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• 2003

In this paper, we present a design and experiment study of high power large diameter backward wave oscillator. Analysis is made within the scope of linear theory of absolute instibility. The Electron beam generator may be atteractive source of high power millimeter microwaves which has simpler structure.