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Comparative Analysis for the Frequency Estimation Algorithms (주파수 변화 추정 알고리즘 비교분석)

  • Kim, Chul-Hun;Kang, Sang-Hee;Nam, Soon-Ryul;Kim, Su-Whoan
    • Proceedings of the KIEE Conference
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    • 2006.07c
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    • pp.1693-1694
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    • 2006
  • Reliable frequency estimation is important for active power control, load shedding and generator protection. Thereby, frequency estimation is researched and some algorithms is proposed. This paper analyzed strength and weakness of each algorithms through comparative analysis of frequency estimation. Used algorithms are Zero Crossing detection, Discrete Fourier Transformation, Least Error Squares.

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Modeling Method for Induction Machines With Stator Winding Faults (유도 전동기의 고정자 권선 사고에 대한 모델링 방법)

  • Nam, Soon-Ryul;Hong, Jung-Gi;Park, Jong-Keun
    • Proceedings of the KIEE Conference
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    • 2003.11a
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    • pp.309-311
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    • 2003
  • 유도 전동기 보호를 위한 계전기 개발을 위해서는 유도 전동기의 내부 사고에 대한 모델링이 선행되어야 한다. 본 논문에서는 유도 전동기의 내부사고 중에서 고정자 권선의 지락 사고에 대한 모델링 방법을 제시하였으며 이를 MATLAB을 이용하여 모의하였다. 제시한 모델링 방법을 이용하여 유도 전동기의 기동 현상을 모의하였으며 이를 EMTP에서 모의한 기동 현상과의 비교를 통하여 제시한 모델링 방법의 타탕성을 검증하였다.

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An Analysis on Objectification of the Concept of Repetition: Focusing on Teacher's and Students' Discourse (중복 개념의 대상화 과정 분석: 교사와 학생의 담론을 중심으로)

  • Ku, Na Young;Lee, Kyeong-Hwa
    • Journal of Educational Research in Mathematics
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    • v.24 no.1
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    • pp.67-82
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    • 2014
  • The term "objectification" has various definitions or perspectives. Nevertheless, it's pursued commonly by groups from various perspectives who emphasize the activities of becoming aware of a process as a totality, realizing that transformations can act on that totality, that is, turning processes into object. The purpose of this study is to identify how students objectify the concept of repetition regarding permutation and combination and find difficulties of objectification focusing on teacher's and students' discourse from common emphasis on previous researches associated with objectification. Students objectified the concept of repetition by replacing talk about processes with talk about objects regarding repetition and using discursive forms that presented phenomena in an impersonal way. The difficulties of objectification were derived from close linkage between the way of using keywords regarding repetition and everyday language.

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Mandelbrot Set Image Generation using 8-connectivity (8-연결성을 이용한 만델브로토 집합 생성 알고리즘 개발)

  • Kim, Yeong-Bong
    • The Transactions of the Korea Information Processing Society
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    • v.4 no.2
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    • pp.596-605
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    • 1997
  • The synamic systrm emplohing the self-squared function, , $f(Z)=z^2+c$, provides the Mandelbrot set which classifies constants c using the divergence of the sequence starting from the origin.To speed-up the generation of Mandelbrot set images, two approaches , called as the divide-and-conquer technique and the triangular boundary tracing technique, have been developed.However , the divede-and-conquer technique genrates sequences of some pixels that so not affect graphical representations of the Mandelbrot set.The triangular boundary tracing tech-mique does noot represent some 8-connected components of the Mandelbrost set.In this paper, we prorose a new ;method which solves the 8-connectivity problem of triangular boundary tracing technique.This algorithm considers the divergence for only pixels which are essential to the graphical repressentation of the Mandelbrot set.It also foves good representations for 8-connected components like hairly structures.

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New Beamforming Technique for ZF-THP Based on SSLNR (SSLNR 기반의 ZF-THP를 위한 새로운 빔형성 기법)

  • Cho, Yong-Seock;Byun, Youn-Shik
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38A no.4
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    • pp.350-359
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    • 2013
  • In this paper, Inter user interference elimination algorithm based on Block Diagonal Geometric Mean Decomposition(BD-GMD) for eliminating inter user interference apply to Zero-Forcing in the Successive Signal to Leakage plus Noise Ratio(SSLNR) in Coordinated Multi-Point Coordinated Beamforming system(CoMP CB). As a result, the leakage power is eliminated. The inter user interference elimination algorithm, however, cannot guarantee the enough desired signal power therefore we perform the channel ordering to overcome this disadvantage and increase the desired signal power. The simulation results show that the proposed scheme provides the improved Bit Error Rate(BER) performance compared with existing SSLNR-Zero-Forcing-Tomlinson Harashima precoding(SSLNR-ZF-THP).

Minimum Movement of a Robot for Sorting on a Cycle (사이클 상에서 정렬을 위한 로봇의 최소 움직임)

  • Kim, Jae-Hoon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.2
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    • pp.429-434
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    • 2017
  • In a graph G=(V, E) with n vertices, there is an unique box which is finally laid on each vertex. Thus each vertex and box is both numbered from 1 to n and the box i should be laid on the vertex i. But, the box ${\pi}$(i) is initially located on the vertex i according to a permutation ${\pi}$. In each step, the robot can walk along an edge of G and can carry at most one box at a time. Also when arriving at a vertex, the robot can swap the box placed there with the box it is carrying. The problem is to minimize the total step so that every vertex has its own box, that is, the shuffled boxes are sorted. In this paper, we shall find an upper bound of the minimum number of steps and show that the movement of the robot is found in $O(n^2)$ time when G is a cycle.

Neighbor Generation Strategies of Local Search for Permutation-based Combinatorial Optimization

  • Hwang, Junha
    • Journal of the Korea Society of Computer and Information
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    • v.26 no.10
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    • pp.27-35
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    • 2021
  • Local search has been used to solve various combinatorial optimization problems. One of the most important factors in local search is the method of generating a neighbor solution. In this paper, we propose neighbor generation strategies of local search for permutation-based combinatorial optimization, and compare the performance of each strategies targeting the traveling salesman problem. In this paper, we propose a total of 10 neighbor generation strategies. Basically, we propose 4 new strategies such as Rotation in addition to the 4 strategies such as Swap which have been widely used in the past. In addition, there are Combined1 and Combined2, which are made by combining basic neighbor generation strategies. The experiment was performed by applying the basic local search, but changing only the neighbor generation strategy. As a result of the experiment, it was confirmed that the performance difference is large according to the neighbor generation strategy, and also confirmed that the performance of Combined2 is the best. In addition, it was confirmed that Combined2 shows better performance than the existing local search methods.

Implementation of an Algorithm that Generates Minimal Spanning Ladders and Exploration on its relevance with Computational Thinking (최소생성사다리를 생성하는 알고리즘 구현 및 컴퓨팅 사고력과의 관련성 탐구)

  • Jun, Youngcook
    • The Journal of Korean Association of Computer Education
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    • v.21 no.6
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    • pp.39-47
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    • 2018
  • This paper dealt with investigating the number of minimal spanning ladders originated from ladder game and their properties as well as the related computational thinking aspects. The author modified the filtering techniques to enhance Mathematica project where a new type of graph was generated based on the algorithm using a generator of firstly found minimal spanning graph by repeatedly applying independent ladder operator to a subsequence of ladder sequence. The newly produced YC graphs had recursive and hierarchical graph structures and showed the properties of edge-symmetric. As the computational complexity increased the author divided the whole search space into the each floor of the newly generated minimal spanning graphs for the (5, 10) YC graph and the higher (6, 15) YC graph. It turned out that the computational thinking capabilities such as data visualization, abstraction, and parallel computing with Mathematica contributed to enumerating the new YC graphs in order to investigate their structures and properties.