• International Journal of Fuzzy Logic and Intelligent Systems
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• v.11 no.1
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• pp.1-7
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• 2011

Most of expert systems use the text-oriented knowledge bases. However, knowledge management using the knowledge bases is considered as a huge burden to the knowledge workers because it includes some troublesome works. It includes chasing and/or checking activities on Consistency, Redundancy, Circulation, and Refinement of the knowledge. In those cases, we consider that they could reduce the burdens by using relational database management systems-based knowledge management infrastructure and convert the knowledge into one of easy forms human can understand. Furthermore they could concentrate on the knowledge itself with the support of the systems. To meet the expectations, in this study, we have tried to develop a general-purposed knowledge conversion tool for expert systems. Especially, this study is focused on the knowledge conversions among text-oriented knowledge base, relational database knowledge base, and decision tree.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.4
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• pp.328-339
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• 2010

A new gasification model for coal char was developed considering the effects of pore structure and solid reaction product (ash) and compared with conventional models. Among various parameters reflecting microscopic pore structure, initial pore surface per unit volume of char was found to have the largest effect on carbon conversions. Reaction studies showed that the proposed model can predict carbon conversion more accurately over a broader range of reaction degree compared to the conventional models. Therefore the model proposed in this study would be useful for the design of pilot or commercial scale gasifiers.

• Journal of Microbiology and Biotechnology
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• v.5 no.3
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• pp.177-180
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• 1995

In horseradish peroxidase-catalyzing polymerization of phenol under the water/dioxane solvent system, the optimal concentration of hydrogen peroxide was found to be 10 mmol/I. Feeding of hydrogen peroxide at its optimal concentration improved the polymerization performance by reducing reaction time and increasing molecular weights. Monomer conversions and the molecular weights of the enzymatically produced polymer were in the ranges of 83.1~94.2$%$ and 58000~68000, respectively.

• Textile Coloration and Finishing
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• v.10 no.5
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• pp.32-38
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• 1998

Glycolides were polymerized by PPG or Pluronic(PN) to give A-B-A block copolyesters consisting of polyglycolide(A) and polypropylene glycol(B) or polyglycolide(A) and PN (B). Lactones were easily copolymerized with polyethers by ester interchange reaction even in the absence of catalyst. It is because PPG and PN are telechelic polyethers having hydroxy groups on their both ends. When the feed ratio of PPG(M$_{n}$=4,000) and PN(M$_{n}$=11,500) were over 5 and 10 wt% .elative to glycolide, respectively, the polymerization of glycolide took place from the terminus hydroxy groups of PPG or PN to produce the desired A-B-A block copolymers in high yields. The molecular weights of the copolymers, which estimated from the monomer conversions and the feed ratios of PPG and PN, could be controlled by changing the kind of terminus hydroxy of polyether and the feed molar ratio of PPG and PN. PN.

• Journal of Korea Multimedia Society
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• v.10 no.12
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• pp.1601-1611
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• 2007

In this paper, we presented geometric CAD watermarking scheme for Architectural design drawings using line, arc, and circle components to prevent infringement of copyright from unlawfulness reproductions and distribution. The conventional CAD watermarking scheme can be applied to both line and arc components. But the proposed scheme consists of line, arc and circle watermarking schemes for three basic components of CAD design. After extracting line, arc and circle components from designed drawing, the watermark is embedded into the length of Line component, the angle of arc component, and the radius of circle component considering the robustness against various geometric transformations. The embedding strengths in each component are determined to be preserving the transparency of the watermark. By experimental result, we confirmed the robustness and the invisibility of embedded watermarks in several conversions of architectural design drawing.

• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.287-289
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• 2009

This paper deals with a parallel processing uninterruptible power supply (UPS) for sudden voltage fluctuation in computer applications to integrate power quality improvement, load voltage stabilization and UPS. To reduce the complexity, cost and number of power conversions, which results in higher efficiency, only one voltage-controlled voltage source inverter (VCVSI) is used. The system provides sinusoidal voltage at the fundamental value of 220V/60Hz for the load during abnormal utility power conditions or grid failure. Also, the system can be operated to mitigate the harmonic current and voltage demand from nonlinear loads and provide voltage stabilization for loads when sudden voltage fluctuation occur, such as sag and swell. System operation simulation demonstrates that the system protects against outages caused by abnormal utility power conditions and sudden voltage fluctuations and changes.

• Journal of Power Electronics
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• v.10 no.5
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• pp.563-571
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• 2010

A model of an advanced aircraft electric power system is developed and studied under variable-speed constant-frequency (VSCF) operation. The frequency of the generator's output voltage is varied from 400-Hz to 800-Hz for different loading scenarios. Power conversions are obtained using 12-pulse power converters. To reduce the harmonic contents of the generator output waveforms, two high-pass passive filters are designed and installed one at a time at the generator terminals. The performance of the two passive filters is compared according to their losses and effectiveness. The power quality characteristics of the studied VSCF aircraft electric power system are presented and the effectiveness of the proposed filter is demonstrated through compliance with the newly published aircraft electrical standards MIL-STD-704F.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.1
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• pp.33-39
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• 2018

As the retrieval accuracy of PWV estimates from GPS measurements is proportional to the accuracy of water vapor WMT, the WMT model is a significant formulation in the conversion of PWV from the GPS ZWD. The purpose of this study is to develop a MWMT model for the retrieval of highly accurate GPS PWV using the radiosonde measurements from six upper-air observing stations in the region of Korea. The values of 1-hr PWV estimated at four GPS stations during one year are used to evaluate the validity of the MWMT model. It is compared to the PWV obtained from radiosonde data that are located in the vicinity of GPS stations. Intercomparison of radiosonde PWVs and GPS PWVs derived using different WMT models is performed to assess the quality of our MWMT model for Korea. The result in this study indicates that the MWMT model is an effective model to retrieve the enhanced accurate GPS PWV, compared to other GPS PWV derived by Korean annual or global WMT models.

• Journal of Powder Materials
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• v.5 no.4
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• pp.273-278
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• 1998

$De-NO_x$ transition metals(Cu, Co)/ZSM-5 catalyst was made by mechanical alloying method, and their microstructures and repeated usage-properties were investigated by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The conversions ability of NO in the catalyst was measured. A part of ZSM-5 in CO/ZSM-5 composite powders was amorphous and the amorphous phase became less stable with increasing Co content. Conversion ability of NO in 10Cu/ZSM-5 powders decreased from 89% to 12% and that in 10Co/ZSM-5 decreased from 22% to 17% by 7 times conversion tests.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.11a
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• pp.445-448
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• 2003

During a time when cellular systems are being deployed in massive scale worldwide, international roaming is becoming increasingly important. This paper presents UIM (User Identification Module) for mobility support, authentication, and service portability between different mobile systems. We also introduce network model based on PASM(Portable Authentication and Mobility Service Machine) which will support signaling protocol and user information conversions with database for roaming between different mobile networks. Stored data types and elements in UIM, logical data structure and configuration, and registration procedures are described here in the case of DCN (Digital CDMA (Code Division Multiple Access) Network System) and GSM (Global System for Mobile Communications).