• Korean Management Science Review
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• v.14 no.1
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• pp.87-105
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• 1997

There have been lots of research on temporal data management for the past two decades. Most of them are based on some logical data model, especially on the relational data model, although there are some conceptual data models which are independent of logical data models. Also, many properties or issues regarding temporal data models and temporal query languages have been studied. But some of them were shown to be incompatible, which means there could not be a complete temporal data model, satisfying all the desired properties at the same time. Many modeling issues discussed in the papers, do not have to be done so, if they take object-oriented data model as a base model. Therefore, this paper proposes a temporal data model, which is based on the object-oriented data model, mainly discussing the most essential issues that are common to many temporal data models. Our new temporal data model and query language will be illustrated with a small database, created by a set of sample transaction.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2006.06a
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• pp.21-27
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• 2006

인과관계는 인간의 인지활동에 있어서 매우 중요한 역할을 한다. 특히 과학과 공학 분야에서 얻은 인과지식은 해당 분야를 이해하는 데에 중요한 역할을 한다. 대표적인 예로, 이들 분야 문서들의 논리적 흐름을 파악하는 데 사용 가능하다. 본 연구에서는, 정보기술 분야의 특허 문서들로부터 얻은 인과 지식을 획득하기 위하여, 문장 내에 나타나는 인과쌍들을 추출하는 방법론을 제시한다. 이를 위하여, 인과관계를 수동으로 태깅하고 관찰하는 작업을 수행하였으며, 태깅을 위한 기준을 설정하였다. 인과쌍의 추출은 패턴을 이용하여 수행하였다.

• Journal of the Korean Applied Science and Technology
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• v.21 no.3
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• pp.238-245
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• 2004

The interaction between anion and zwitterionic surfactants was investigated by means of surface tension, NMR spectroscopy, and fluorescence studies. These systems are N-tetradecyloxymethyl-N,N-dimethyl betaine ($C_{14}$, TDB), N-octadecyloxymethyl-N,Ndimethyl betaine ($C_{18}$, ODB), and sodium dodecylethoxy sulfate (SDE). These systems show a composition dependency in micellar properties. When the molar fraction of TDB and ODB was about 0.6, the cmc values of these systems showed minima, whereas the solubilized amount of a water insoluble dye, NMR line width showed maxima. These changes comes from the intramolecular complexes formed in the mixed micelles. The complexes are due to the electrostatic interaction of oppositely charged head groups of betaine and sodium dodecylethoxy sulfate. A comparison of betaine and SDE alkyl methylene group line widths to those of n-methyl group indicates that the interior of the micelle in the restricted region is more immobile than the head group.

• Journal of the Korean Applied Science and Technology
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• v.30 no.3
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• pp.380-386
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• 2013

N,N,N-Trimethyl-10-nitrophenoxy decylammonium bromide (N10TAB) and N,N,N,N-Tetramethyl-bis-[10-nitrophenoxy decyl]-1,6-hexanediammonium dibromide (N10-6-10N), bearing aromatic nitrophenoxy group in the end of their hydrophobic chains have been prepared, and their properties in aqueous solutions have been studied by conductivity and H-NMR spectroscopy. Below the critical micelle concentration N10-6-10N form premicelle with two or three surfactant molecules. Beyond the critical micelle concentration two molecules have strong self-aggregation ability and form micelles of rather small size and with small aggregation numbers. H-NMR at different concentrations give the informations on the environmental changes of the surfactants on their micellization progress.

• Bulletin of the Korean Mathematical Society
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• v.50 no.6
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• pp.1781-1797
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• 2013

Let x : $M{\rightarrow}\mathbb{R}^n$ be an n - 1-dimensional hypersurface in $\mathbb{R}^n$, L be the Laguerre Blaschke tensor, B be the Laguerre second fundamental form and $D=L+{\lambda}B$ be the Laguerre para-Blaschke tensor of the immersion x, where ${\lambda}$ is a constant. The aim of this article is to study Laguerre Blaschke isoparametric hypersurfaces and Laguerre para-Blaschke isoparametric hypersurfaces in $\mathbb{R}^n$ with three distinct Laguerre principal curvatures one of which is simple. We obtain some classification results of such isoparametric hypersurfaces.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.468-472
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• 2007

For small capacity rectifier circuits such as these for consumer electronics and appliances, capacitor input type rectifier circuits are generally used. Consequently, various harmonics generated within the power system become a serious problem. Various studies of this effect have been presented previously. The absence of switching devices makes systems more tolerant to over-load, and brings low radio noise benefits. We propose a power factor correction scheme using a LC resonant in commercial frequency without switching devices. In this method, It makes a sinusoidal wave by widening conduction period using the current resonance in commercial frequency, Hence, the harmonic characteristics can be significantly improved, where the lower order harmonics, such as the fifth and seventh orders are much reduced. The result are confirmed by the theoretical and expermental implementations

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.11
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• pp.741-746
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• 2004

When investigating a control problem for network based control systems, the main issue is network-induced delay. This delay can degrade the performance of control systems designed without considering the delay and even destabilize the system. In this paper, we consider the stabilization of network based control systems, where there is bounded time-varying delay. This delay is treated like parameter variation of a discrete time system. The state feedback controller design is formulated as linear matrix inequality. Finally, we show that the stability of control systems designed with considering the delay is superior to that is not so.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.236-238
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• 2005

In this paper, we propose a new discrete-time predictive current controller for a PMLSM(permanent magnet linear synchronous motor). The main objectives of the current controllers are that the measured stator current is tracked the command current value accurately and the transient interval is shorten as much as possible, in order to obtain high-performance of ac drive system. The conventional predictive current controller is hard to implement in full digital current controller since a finite calculation time causes a delay between the current sensing time and the time that take to apply the voltage to motor. A new control strategy is the schema that gets the fast adaptation of transient current change, the fast transient response tracking. Moreover, the simulation results will be verified the improvements of Predictive controller and accuracy of the current controller.

• Annual Conference of KIPS
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• 2003.05b
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• pp.1293-1296
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• 2003

ebXML의 핵심 컴포넌트(Core Component)는 범 산업 분야 및 다양한 환경에서 재사용 가능하고 컨텍스트(context)에 영향을 받지 않는 일반적인 빌딩블록(building block)으로, 비즈니스 문서를 구성하기 위한 가장 기본 요소이다. 이러한 핵심 컴포넌트는 비즈니스 컨텍스트에 의해 BIE(Business Information Entity)를 이루게 되며 Syntax binding을 통해 XML Schema, DTD 등의 형태로 표현된다. 따라서, ebXML환경에서 사용되는 비즈니스 문서를 포함하여 다양한 종류의 XML Schema, DTD, XML 관련 문서를 쉽게 저작(생성, 검증, 편집)할 수 있는 도구가 필요하다. 본 논문에서는 이러한 요구사항에 적합한 ebXML CC 기반 BD(Business Document) 저작도구로 범용적으로 사용할 수 있는 Schema.DTD 기반 XML 문서 편집기, Schema 문서 편집기, DTD 문서 편집기로 구성된 XDocBuilder를 설계 및 구현하였다.

• Proceedings of the Korean Society of Veterinary Clinics Conference
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• 2006.05a
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• pp.153-153
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• 2006