• Journal of Electrical Engineering and Technology
• /
• v.8 no.6
• /
• pp.1380-1388
• /
• 2013

The conventional graphical representation of the instantaneous compensation power flow for single-phase active power filters(APFs) simply represents the active power flow and the reactive power flow which flowing between the power source and the active filter / the load. But, this method does not provide the information about the rectification mode and the compensation mode of APFs, especially, the loss for each mode was not considered at all. This is very important to understand the compensation operation characteristics of APFs. Therefore, this paper proposes the graphical representation of the instantaneous compensation power flow for single-phase APFs considering the instantaneous rectification mode and the instantaneous inversion mode. Three cases are verified in this paper - without compensation, with compensation of the active power 'p' and the fundamental reactive power 'q', and with compensation of only the distorted power 'h'. To ensure the validity of the proposed approach, PSIM simulation is achieved. As a result, we could confirm that the proposed approach was easy to explain the instantaneous compensation power flow considering the instantaneous rectification mode and the instantaneous inversion mode of APFs, also, Total Harmonic Distortion(THD)/Power Factor (P.F) and Fast Fourier Transform(FFT) analysis were compared for each case.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.07a
• /
• pp.1069-1072
• /
• 2001

We described a method resonant mode identification in dielectric-rod loaded cylindrical cavity resonators. Resonant frequency of dielectric loaded cavity is calculated by analyzing the characteristic equation. The characteristic equation is solved by using the ContourPlot graph of Mathematica. As the result of comparing calculation value and experimental value of resonant frequencies, we know that the field representation of non-decaying mode is exact. The contour graph method is not a method using approximated representation of electromagnetic field variation at the outer area of dielectric in the resonators but a method using exact representation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.15 no.1
• /
• pp.37-45
• /
• 2002

We described a method of resonant mode identification in dielectric-disc loaded cylindrical cavity resonators. The characteristic equations are solved using the ContourPlot graph of Mathematica. Contour graph method uses graphical method. It is comparable with numerical method. The numerical method is very difficult mode identification. The analysis is based on the approximated electromagnetic representation which is only concentrated on the calculation of resonant frequencies, and a mode identification of resonant frequencies has not been covered. However, It is possible to calculate precise resonant frequencies and to identify the mode of resonant frequencies using the contour graph method. The contour graph method is not a method using approximated representation of electromagnetic field variation at the outer area of dielectric in the resonators. It is a method using enact representation.

• Journal of the Optical Society of Korea
• /
• v.10 no.4
• /
• pp.162-168
• /
• 2006

The variation of global coherence on propagation plane by plane is examined in the framework of coherent mode representation. It is explained through concrete examples that the global coherence may in general be enhanced, may be reduced, or may not change. When the mode functions form a complete set and the corresponding eigenvalues are in nitely degenerate, there necessarily develops a certain amount of global coherence on propagation, which is the essence of van Cittert-Zernike theorem. The propagation generates a certain pattern of the eigenvalue spectrum from the initial flat one and this is shown to be related to the non-unitarity of the propagation kernel.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.19 no.9
• /
• pp.1702-1709
• /
• 1994

In the postprocessing of Hangul recognition system, the storage structure of contextual information is an important matter for the recognition rate and speed of the entire system. Trie in general is used to represent the context as word dictionary, but the memory space efficiency of the structure is low. Therefore we propose a new structure for word dictionary that has better space efficiency and the equivalent merits of trie. Because Hangul is a compound language, the language can be represented by phonemes or by characters. In the representation by phonemes(P-mode) the retrieval is fast, but the space efficiency is low. In the representation by characters(C-mode) the space efficiency is high, but the retrieval is slow. In this paper the two representation methods are combined to form a hybrid representation(H-mode). At first an optimal level for the combination is selected by two characteristic curves of node utilization and dispersion. Then the input words are represented with trie structure by P-mode from the first to the optimal level, and the rest are represented with sequentially linked list structure by C-mode. The experimental results for the six kinds of word set show that the proposed structure is more efficient. This result is based on the fact that the retrieval for H-mode is as fast as P-mode and the space efficiency is as good as C-mode.

• Journal of the Optical Society of Korea
• /
• v.12 no.2
• /
• pp.103-106
• /
• 2008

It is shown that the two mode representations, one with vector modes and the other with scalar modes, for the cross spectral density matrices of electromagnetic beams are equivalent to each other. In particular, we suggest a method to find the vector modes from the scalar modes and formulate the cross spectral density matrix as a correlation matrix.

• School Mathematics
• /
• v.18 no.1
• /
• pp.127-141
• /
• 2016

This study analyzes modes related to use of graph representation that appears to solve high school students quadratic function problem based on the graph using modes of Chauvat. It was examined the extent of understanding of the quadratic function of students through the flexibility of the representation of the Bannister (2014) from the analysis. As a result, the graph representation mode in which a high school students are mainly used is a nomographic specific mode, when using operational mode, it was found to be an error. The flexibility of Bannister(2014) that were classified to the use of representation from the point of view of the object and the process in the understanding of the function was constrained operation does not occur between the two representations in understanding the function in the process of perspective. Based on these results, the teaching on use graph representation for the students in classroom is required and the study of teaching and learning methods can understand the function from various perspectives is needed.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• v.2 no.1
• /
• pp.111-129
• /
• 1998

An integral equation representation of cracks was presented, which differs from well-known "dislocation layer" representation. In this new representation, an integral equation representation of cracks was developed and coupled to the direct boundary-element method for treatment of cracks in plane finite bodies. The method was developed for in-plane(modes I and II) loadings only. In this paper, the method is formulated and applied to mode III problems involving smooth or kinked cracks in finite region. The results are compared to exact solutions where available and the method is shown to be very accurate despite of its simplicity.

• Journal of Welding and Joining
• /
• v.18 no.4
• /
• pp.104-110
• /
• 2000

An integral equation representation of cracks was presented, which differs from well-known "dislocation layer" representation. In this new representation, an integral equation representation of cracks was developed and coupled to the direct boundary-element method for treatment of cracks in plane finite bodies. The method was developed for in-plane (modes I and II) loadings only. In this paper, the method is formulated and applied to mode III problems involving smooth or kinked cracks in finite region. The results are compared to exact solutions where available and the method is shown to be very accurate despite of its simplicity.implicity.

• Journal of the Korean Chemical Society
• /
• v.56 no.3
• /
• pp.363-370
• /
• 2012

The purpose of the study was to classify scientific models in the seventh grade science textbooks of the 2007 revised science curriculum. The three chapters of 'three states of material', 'motion of molecule', and 'change of state and energy' were investigated. There were two types of the scientific model as 'mode of representation' and 'attribute of representation'. The mode of representation was composed of 'action model', 'analogical model', 'symbolic model', and 'theoretical model' and the attribute of representation was composed of 'static model' and 'dynamic model'. The results showed that the action model and the analogical model were used primarily in mode of representation. The dynamic model were widely used in attribute of representation. Area of matters dealt with conception of molecules and aimed for students to understand the arrangement and movement of molecule microscopically about macroscopic state in a daily life. Tis study could help to recognize the limitations of scientific models on current textbooks and offer more useful information in planning lessons and organizing textbooks for the future.