• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.6 s.121
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• pp.584-590
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• 2007

In this paper, the efficiency of power amplifier has been maximized by the application of EER structure, and the linearity has been improved by using PBG structure. This paper has proposed a design of power amplifier in class-F to get the PAE, and to control dynamic power using envelope detector. PBG structure gets high-linearity by removing harmonics arisen from the mismatching of matching circuit. The PAE and the 3rd order IMD have been improved 34.64%, 6.65 dB compared with those of conventional Doherty amplifier, respectively.

• Journal of Internet Computing and Services
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• v.19 no.5
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• pp.107-113
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• 2018

Object-oriented databases (OODBs) canbe used for many non-traditional database application areas such as computer-aided design, etc. Usually those application areas require advanced modeling power for expressing complicated relationships among data sets. OODBs have more distinguished features than the traditional relational database systems. One of the distinguished characteristics of OODBs is class hierarchy (also called inheritance hierarchy). A class hierarchy in an OODB means that a class can hand down the definitions of the class to the subclass of the class. In other words, a class is allowed to inherit the definitions of the class from the superclass. In this paper, we present performance evaluation metrics for class hierarchy in OODBs from a concurrency control perspective. The proposed performance metrics are developed to determine which concurrency control scheme in OODBs can be used for a given class hierarchy. In this study, in order to develop performance metrics, we use class hierarchy structure (both of single inheritance and multiple inheritance), and data access frequency for each class. The proposed performance metrics will be also used to compare performance evaluation for various concurrency control techniques.

• Honam Mathematical Journal
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• v.36 no.2
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• pp.387-398
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• 2014

In this paper, we give a structure theorem for a class of Gorenstein ideal of grade 4 which is the sum of an almost complete intersection of grade 3 and a Gorenstein ideal of grade 3 geometrically linked by a regular sequence. We also present the Hilbert function of a Gorenstein ideal of grade 4 induced by a Gorenstein matrix f.

• Honam Mathematical Journal
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• v.35 no.2
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• pp.147-161
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• 2013

In this paper we determine certain class of $n$-dimensional QR-submanifolds of maximal QR-dimension isometrically immersed in a quaternionic space form, that is, a quaternionic K$\ddot{a}$hler manifold of constant Q-sectional curvature under the conditions (3.1) concerning with the second fundamental form and the induced almost contact 3-structure.

• East Asian mathematical journal
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• v.25 no.2
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• pp.127-140
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• 2009

In this paper a general class of analytic functions involving a convolution structure is introduced. Among the results investigated are the various results depicting useful properties and characteristics of this function class by employing the techniques of differential subordination. Relevances of the main results with some known results are also mentioned briefly.

• The Transactions of the Korea Information Processing Society
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• v.7 no.12
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• pp.3829-3839
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• 2000

The UML(Unified Modeling Language) Class Diagram which is a part of structure of UML is fit for Object Modeling, and more recently, as the appearance of UXF(UML eXchange Format) UML Class Diagram by itself, can be exchanged in many other different system document. So this paper suggest the conversion system from UML Class Diagram to XML DTD. As this we can easily transformation and saving the UML Class Diagram that is the standard of Modeling Language to XML document which is so reusable. Also it can give a flexible method for the representation to the logical structure of document in various way because of converting XML DTD.

• Journal of the Korea Society of Computer and Information
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• v.13 no.3
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• pp.1-13
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• 2008

Gestwicki et. al. proposed the technique that detects and predicts the structure of object diagrams from class diagrams to get the improved drawing of object graphs. Their approach finds two predictable structures - recursive clusters and leaf clusters from class diagrams. Their approach is not practical to be applied to real programs, because the starting point is class diagram. In this work, we improve and implement their technique to apply to Java classes. We obtain the structure and relationships of classes and clusters extracted from class files. This information can be provided and used as a template of object graphs for Java execution visualization tools like JIVE.

• Proceedings of the Korean Reliability Society Conference
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• 2002.06a
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• pp.305-305
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• 2002

A continuum structure function is a non-decreasing mapping from the unit hypercube to the unit interval. Within the class of continuum structure functions, new axiomatic characterizations of the Natvig and the Barlow-Wu subclass are obtained.

• School Mathematics
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• v.17 no.2
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• pp.203-222
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• 2015

This study analyzed the classroom discourse between teacher and students based on the Mehan(1979a)'s theory to examine the characteristics of the classroom discourse between teacher and students in high school statistics class. The results of this study on the structure of class showed that the statistics class in this study adopted knowledge transmission-oriented teacher-led class in which the framework of introductiondevelopment- arrangement, which is Mehan's basic 3 stages, is clearly represented. The results of examining I-R-E sequence showed that $I_T-R_T$ structure, in which the teacher asks questions and the teacher talks about the answer, frequently appeared. And the statistics class in this study was monological class in which students hardly participated. Through these results of this study, it was found that teacher should form the statistical context, in which students can participate in discourse, and build discourse learning community and induce argumentational discourse through metaprocess elicitation.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.2
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• pp.85-89
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• 2011

In this paper, a novel Class-E power amplifier using metamaterials has been realized with one RF LDMOS diffusion metal-oxide-semiconductor field effect transistor. The CRLH structure can lead to metamaterial transmission line with the Class-E power amplifier tuning capability. The CRLH TL is achieved by the frequency offset and the nonlinear phase slope of the CRLH TL for the matching network of the power amplifier. Also, the proposed power amplifier has been realized by using the CRLH structure in the output matching network for better efficiency. Operating frequencies are chosen at 13.56 MHz in this work. The measured results show that the output power of 39.83 dBm and the gain of 11.83dB was obtained. At this point, we have obtained the power-added efficiency (PAE) of 73 % at operation frequency.