• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1986.10a
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• pp.198-200
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• 1986

In this paper, the optical modem for data link realization is designed with the advantages of optical fiber : large handwidth, no electromagnetic interference, high speed and long-haul communications. Biphase cording format is used for the sync, and async, transmissions. Modem interface conform to the CCITT V.24 standard for the compatibility with existing systems. 0/E and E/0 converters are designed using LED-APD pair for long wave length and LD-APD for short wave length, respectively. As a result, the system is capable of transmitting at any bps within dc to 200Kbps in async, and at 1200bps up to 57.6Kbps in sync. transmission.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.3
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• pp.250-256
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• 2015

We present a novel method to model the body posture of a worm for vision-based automatic monitoring and analysis. The worm considered in this study is a Caenorhabditis elegans (C. elegans), which is popularly used for research in biological science and engineering. We model the posture by an open chain of a few curved or rigid line segments, in contrast to previously published approaches wherein a large number of small rigid elements are connected for the modeling. Each link segment is represented by only two parameters: an arc angle and an arc length for a curved segment, or an orientation angle and a link length for a straight line segment. Links in the proposed method can be readily related using the Denavit-Hartenberg convention due to similarities to the kinematics of an articulated manipulator. Our method was tested with real worm images, and accurate results were obtained.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.63-68
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• 2022

Two wavelength reconfigurable optical nodes are designed. One for 20km or shorter link length, and the other for up to 60km link length. While the first one requires no dispersion compensation, the latter needs dispersion compensation fiber included in the node, which requires additional optical amplifier to compensate the insertion loss of DCF. We calculate all the optical path losses in both cases using the typical value of optical components in the market to see the feasibility of the designed optical node. The minimum received power in the node is calculated to be -21.5dBm without DCF and -12.5dBm with DCF, respectively. These received powers are above the receiver sensitivity both for OC-48 and OC-192 according to the previous work.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.1
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• pp.96-103
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• 1997

We developed the prototype of 4-channel WDM link with erbium-doped fiber amplifiers. Bit rate of each channel was 2.5Gb/s. The unrepeatered transmission over 120km with DSF was achieved and the transmission length was extended to 240km using two EDFAs.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.178-181
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• 2003

Intermediate cooling for current lead is used of thermal link in conduction cooling and cooled of itself in liquid cooling because it is put in liquid. If a existing formula for cooling load and optimal diameter-length of current lead is applied, it generate some more cooling load. Therefore, variation of thermal link height and holding depth in liquid is considered. This result is used of reducing cooling load of current lead occupying most of superconducting system load and applying liquid/conduction cooling systems.

• Fibers and Polymers
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• v.7 no.3
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• pp.310-316
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• 2006

In this article, an attempt has been made to explain the failure mechanism of spun yams. The mechanism includes the aspects of generation and distribution of forces on a fibre under the tensile loading of a yam, the free body diagram of forces, the conditions for gripping and slipping of a fibre, and the initiation, propagation, and ultimate yam rupture in its weakest link. A simple mathematical model for the tenacity of spun yams has been proposed. The model is based on the translation of fibre bundle tenacity into the yam tenacity.

• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.618-620
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• 1998

We implemented PanelLink flat panel display receiver which can be used for testing SXGA($1280{\times}1024$) TFT LCD panel. We've got optimal analog input voltage to get stable image according to cable length. And we commented the way to reduce EMI.

• Journal of Advanced Navigation Technology
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• v.13 no.1
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• pp.27-33
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• 2009

New optical transmission link techniques improving performance of WDM channels, each channel have bit rate of 40 Gbps, are proposed. The proposed optical link configuration consist of optical phase conjugator (OPC) placed at middle of total transmission length, and dispersion management (DM) as a role of compensating dispersion cumulated in transmission line. It is confirmed that Q-factor of total channels are improved by combining OPC and DM in optical transmission link as a result of following fact; DM not only mitigate the cumulated dispersion in total transmission line but also help OPC to compensate optical nonlinearities. And, it is confirmed that the improvement of Q-factor of overall WDM channels depends on net residual dispersion (NRD) of optical link.

• Phonetics and Speech Sciences
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• v.6 no.3
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• pp.81-89
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• 2014

Korean English learners tend to have difficulty perceiving and producing English vowels. The purpose of this study is to examine a link between perceived and produced vowel spaces of Korean learners of English. Sixteen Korean male and female participants perceived two sets of English synthetic vowels on a computer monitor and rated their naturalness. The same participants produced English vowels in a carrier sentence with high and low pitch variation in a clear speaking mode. The author compared the perceived and produced vowel spaces in terms of the pitch and gender variables. Results showed that the perceived vowel spaces were not significantly different in either variables. Korean learners perceived the vowels similarly. They did not differentiate the tense-lax vowel pairs nor the low vowels. Secondly, the produced vowel spaces of the male and female groups showed a 25% difference which may have come from their physiological differences in the vocal tract length. Thirdly, the comparison of the perceived and produced vowel spaces revealed that although the vowel space patterns of the Korean male and female learners appeared similar, which may lead to a relative link between perception and production, statistical differences existed in some vowels because of the acoustical properties of the synthetic vowels, which may lead to an independent link. The author concluded that any comparison between the perceived and produced vowel space of nonnative speakers should be made cautiously. Further studies would be desirable to examine how Koreans would perceive different sets of synthetic vowels.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.12A
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• pp.945-950
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• 2003

The link aggregation between 10GbE switches requires an advanced frame distribution method to be properly and efficiently applied. The fixed or dynamic frame distribution methods, formerly proposed, cannot fully utilize the aggregated links, where the receiving terminal only attaches to a pre-specified link among multiple physical links. A frame distribution method using tagging is proposed for the link aggregation between 10GbE switches to solve this problem. We compared the performance of the proposed method with those of the fixed and dynamic frame distribution methods. As a result, the proposed method shows a better performance when the applied load is below 0.7 and the average length of the frames is longer than 954 bytes.