• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2935-2938
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• 2003

A new Valley-fill circuit for improving PF(power factor) is proposed in this paper. The proposed topology combines Valley-fill rectifier and an additional inductor for boosting. In the proposed circuit, a shapc of input current is related to the PWM duty cycle. The boosting inductor makes improve PF by the electric charge transfer action. The operation principle and the shape of input current arc analyzed as applied the boosting inductor. The optimum value of boosting inductor is determined. A 100W single-stage converter has been designed and tested. Experimental results are presented to verify the validity of the proposed converter.

• Journal of Korean Institute of Industrial Engineers
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• v.5 no.2
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• pp.15-20
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• 1979

Information on the future availability of invested funds provides a decision maker with additional insight into the characteristics of alternatives in sequential investment analysis. The flexibilty to pursue newly emergent investment opportunities is an important property of decision alternatives that describes the future mobility of invested funds. The primary purpose of this paper is to propose a method for measuring flexibility using the concept of negative project balance with project abandonment option.

• Proceedings of the IEEK Conference
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• 2000.06c
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• pp.101-104
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• 2000

In this paper, we implement a video conference system, which connects remote PCs. Each system receives video and audio data from devices attached to a PC and compresses them by using CODECs. It sends the compressed data to the opponent. Compared to the existing ones, the proposed system can combine two video streams into a new one. Thus, additional video data can be transferred to the opponent during a call.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.5
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• pp.63-63
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• 2001

디바이스의 크기가 0.25㎛이하로 축소됨에 따라 DRAM(Dynamic Random Access Memory) 제조업체들은 칩 크기를 줄이고 지역적인 배선으로 사용하기 위해서 기존의 텅스텐-폴리사이드 비트-선에서 텅스텐 비트-선으로 대체하고 있다. 본 논문에서는 다양한 RTP 온도와 추가 이온주입을 사용하여 낮은 저항을 갖는 텅스텐 비트-선 제조 공정에 대해 다루었다. 그 결과 텅스텐 비트선 저항에 중요한 메계변수는 RTP Anneal 온도와 BF₂ 이온 주입 도펀트임을 알 수 있었다. 이러한 텅스텐 비트-선 공정은 고밀도 칩 구현에 중요한 기술이 된다.

• Communications for Statistical Applications and Methods
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• v.9 no.3
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• pp.787-797
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• 2002

Partial residual plots, augmented partial residual plots and CERES plots are basic diagnostic tools for dealing with curvature as a function of specific predictors in regression problem. However, it is known that these plots can miss a curve or show a false curve in some cases such as predictors are related each other. Dynamic display of these plots is developed and applied. Examples demonstrate that dynamic plots are useful for obtaining additional Information on the curvature.

• Journal of applied mathematics & informatics
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• v.26 no.1_2
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• pp.389-393
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• 2008

This paper describes a single-server queue where the server is unavailable during some intervals of time, which is referred to as vacations. The major contribution of this work is to derive general formulas for the additional delay in the vacation models of the single vacations, head of line priority queues with non-preemptive service, and multiple vacations and idle time.

• Communications for Statistical Applications and Methods
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• v.14 no.2
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• pp.309-316
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• 2007

In this paper, we decompose the whole likelihood based on grouped data into conditional likelihoods and study the approximate contribution of additional inspection to the efficiency. We also combine the conditional maximum likelihood estimators to construct an approximate maximum likelihood estimator. For an exponential distribution, we see that a large inspection size does not increase the efficiency much if the failure rate is small, and the maximum likelihood estimator can be approximated with a linear function of inspection times.

• Journal of Electrical Engineering and information Science
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• v.3 no.3
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• pp.336-341
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• 1998

We describe the architecture of an optical cross-connect (OXC) which is modular in structure and is able to be upgraded to a virtual wavelength path by adding wavelength converters. The additional feature of the OXC is the all-optical nature. It can be implemented with commercial components including mechanical optical switches. As a result of the test on the experimental OXC, it has been shown that 2.5 Gb/s signal can be transmitted via the OXC through 100 km length o an ordinary single mode fiber with 3 dB penalty.

• Proceedings of the KSRS Conference
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• v.1
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• pp.43-46
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• 2006

The main tsunami wave triggered by the December 2004 Sumatra tsunami was detected in the ocean south of India by satellite altimeters on Jason, Topex/Poseidon and Envisat. All three altimeters also detected shorter-wavelength (10 to 100 km), slower-propagating surface waves, spreading from the site of the earthquake. The shorter waves give additional information about the tsunami event, and can be used to better define the generating region in this, and future tsunamis. The properties of the area of shorter tsunami-generated waves may also be important in designing a future satellite-based detection system.

• Communications for Statistical Applications and Methods
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• v.8 no.3
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• pp.797-803
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• 2001

This paper obtained Bayes prediction density for the spatial linear model with non-informative prior. It showed the results that predictive inferences is completely unaffected by departures from the normality assumption in the direction of the elliptical family and the structure of prediction density is unchanged by more than one additional future observations.