• Journal of The Korean Astronomical Society
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• v.38 no.4
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• pp.385-414
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• 2005

We have searched for infrared emission from supernova remnants (SNRs) included in the Spitzer Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) field. At the positions of 100 known SNRs, we made 3.6, 4.5, 5.8, and $8.0{\mu}m$ band images covering the radio continuum emitting area of each remnant. In-depth examinations of four band images based on the radio continuum images of SNRs result in the identification of sixteen infrared SNRs in the GLIMPSE field. Eight SNRs show distinct infrared emission in nearly all the four bands, and the other eight SNRs are visible in more than one band. We present four band images for all identified SNRs, and RGB-color images for the first eight SNRs. These images are the first high resolution (<2') images with comparative resolution of the radio continuum for SNRs detected in the mid-infrared region. The images typically show filamentary emission along the radio enhanced SNR boundaries. Most SNRs are well identified in the 4.5 and $5.8{\mu}m$ bands. We give a brief description of the infrared features of the identified SNRs.

• Journal of the Korean Society for Library and Information Science
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• v.39 no.4
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• pp.89-104
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• 2005

This article identifies an emerging research paradigm and monitors the changes in digital preservation area using CiteSpace, a Java application which supports visual exploration with knowledge discovery in bibliographic databases. 74 articles on digital preservation field covering the time period from 1990-2005 were extracted from Web of Science. According to the result of analysis, core knowledge domains in digital preservation are technical preservation strategies, information network and preservation system, knowledge management and electronic government.

• Corrosion Science and Technology
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• v.4 no.5
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• pp.201-206
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• 2005

Starting with the meaning of the word quality, diverse concepts connoted by the term are examined. Instead of a bathtub curve, the desirable shape of a failure rate covering the entire life of a good product, which might be called hockey-stick line, is introduced. From the hockey-stick line and the definition of reliability, two measurements are extracted. The terms r-reliability (failure rate) and durability (product life) are explained. The conceptual analysis of failure mechanics explains that reliability technology pertains to design area. The desirable shape of hazard rate curve of electronic items, hockey-stick line, clarifies that Mean-Time-to-failure (MTTF) as the inverse of failure rate can be regarded a nominal life. And Bx life, different from MTTF, is explained. Reliability relationships between components and set products are explained. Reshaped definitions of r-reliability and durability are recommended. The procedure to improve reliability and the reasons for failing to identify failure mode are clarified in order to search right solutions. And generalized Life-Stress failure model is recommended for the calculation of acceleration factor.

• Elastomers and Composites
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• v.33 no.1
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• pp.17-26
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• 1998

Natural rubber was filled with 8 commercial carbon blacks covering range of rubber-grade products at different levels of filler loadings in order to investigate physical compound and vulcanizate properties. It was found that the curves of rubber property vs filler loading of both uncured compounds and vulcanizates can be superposed to one single master curve by introducing an effective volume fraction which is based on CDBP. The effective volume fraction, $V_{EFF}$ was utilized to explain the variation of the stiffness of all rubber compounds. The surface area-corrected effective volume fraction, V', was utilized to explain the formation of bound rubber, rebound and lambourn wear.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.973-976
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• 2005

In IEEE 802.15.4 (Low-Rate Wireless Personal Area Network) specification, a successful reception and validation of a data or MAC command frame can be confirmed with an acknowledgment. However, the specification does not support security for acknowledgment frame; the lack of a MAC covering acknowledgments allows an adversary to forge an acknowledgment for any frame. This paper proposes an identity authentication mechanism at the link layer for acknowledgment frame in IEEE 802.15.4 network. With the proposed mechanism there is only three bits for authentication, which can greatly reduce overhead. The encrypted bit stream for identity authentication will be transmitted to device by coordinator within association process. Statistical method indicates that our mechanism is successful in handling MAC layer attack.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.778-784
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• 2002

FFU are used increasingly by the microeleceronics industry to provide clean recirculating air for the fabrication of integrated circuits and laminar flow air. There may be several hundred ffu in a large cleanroom, covering 100% of the ceiling area. Hence, there is of often knowledge in the inside and outside of the country the flu give rise to noise & vibration trouble to microelectronics industry. Noise ＆ Vibration control for satisfication about noise ＆ vibration criteria in TFT-LCD factory cleanroom be in need of exact noise & vibration data of accurence from utility & equipment that can be exert a bad influence upon cleanroom. In this pater, hence we found out noise and vibration properities of ffu by using experimental method. And, we performed noise ＆ vibration analysis about noise it vibration level in cleanroom using semiempirical method for quantative approach about noise ＆ vibration level in cleanroom.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.625-629
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• 2014

In this paper, a tile projector for the active control of low-frequency underwater echoes is studied using finite element method. Compared to the existing underwater actuators used for echo reduction, the tile projector is better suited for covering a wide area such as the hull of a submarine. In order to actively match the acoustic impedance at the water-object interface, the projector is driven to radiate a pressure wave that is the inverted replica of the echo at the interface. Finite element simulations demonstrate significant echo reductions due to the active impedance matching by the tile projector.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.7
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• pp.71-80
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• 2004

A system for estimating daily paddy irrigation water requirements was developed to simulate daily stream flows that reflect various upstream and downstream return flows from river basin. Evapotranspiration in paddy fields was estimated using the modified Penman equation. Daily irrigation water requirements of paddy fields were calculated by multiplying the paddy area and the daily decrease in ponding depth. The system was constructed almost completely using images, grids, etc. in Visual Basic 6.0. The developed model was verified in the Damyang dam, and was used to estimate daily paddy irrigation water requirements at 12 small watersheds in Geum river basin for 20 years, from 1983 to 2002, covering paddy field areas of $3,332\~26,422$ ha. The results on the runoff analysis on the inflow to the Daecheong multi-purpose dam with various return flows were satisfactory. They were reasonable compared to the scenario where return flows were not considered.

• Journal of Communications and Networks
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• v.14 no.6
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• pp.672-681
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• 2012

A potential breakthrough of the electrification of the vehicle fleet will incur a steep rise in the load on the electrical power grid. To avoid huge grid investments, coordinated charging of those vehicles is a must. In this paper, we assess algorithms to schedule charging of plug-in (hybrid) electric vehicles as to minimize the additional peak load they might cause. We first introduce two approaches, one based on a classical optimization approach using quadratic programming, and a second one, market based coordination, which is a multi-agent system that uses bidding on a virtual market to reach an equilibrium price that matches demand and supply. We benchmark these two methods against each other, as well as to a baseline scenario of uncontrolled charging. Our simulation results covering a residential area with 63 households show that controlled charging reduces peak load, load variability, and deviations from the nominal grid voltage.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.328-333
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• 2004

With the introduction of KTX, in my view it is necessary to secure the reliability of high-speed trains, make them stabilized at the earliest moment possible, and completely digest them as our own system for the purpose of being second to none in the area of railroad business. I am going to study in this thesis through analysis of train failures by help of MKBSF calculation, breaking from the convention in maintaining the high-speed trains, in order to establish and apply the computerized system called as RCM (Reliability Centered Maintenance), foster manpower in charge of the reliability maintenance, and realize the scientific and efficient maintenance covering the whole field of maintenance. Depending on how efficiently and scientifically we can perform the maintenance activities, we will be able to not only reduce the maintenance cost but also ensure the railroad security, and as a natural consequence improve the railroad image much better.