• Proceedings of the Korea Information Processing Society Conference
• /
• 2002.11a
• /
• pp.455-458
• /
• 2002

분기를 가지는 대상객체에 대한 가상 네비게이션 시 네비게이션 경로를 지정하기 위하여 일반적으로 반복적인 형태학적 연산(Iterative Morphological Operation)중 세선화(thining)연산을 기반으로 한 골격화(skeletonization)기법들이 널리 사용되었다. 이러한 방법은 반복적인 세선화 연산 수행과정을 거쳐야하므로 수행효율성이 떨어지고, 잡음에 의하여 잘못된 경로를 생성하기 쉽다. 본 연구에서 수행효율성을 개선하고, 잡음에 안정적으로 네비게이션 경로를 추적하기 위하여 영역 중심점 선형 보간 기법을 기반으로 한 네비게이션 경로추적 기법을 제안한다. 본 제안 기법에서는 2 차원 영상 분할 후, 분할 영상에 대한 영역의 수와 영역 중심점을 기반으로 분기위치를 추적하고, 분기영역에서의 영역 중심점 선명 보간을 통하여 자연스러운 네비게이션 경로를 생성한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2012.10a
• /
• pp.279-282
• /
• 2012

In this paper, a hardware architecture of phase calculator for 3D image processing is proposed. The designed phase calculator, which adopts a pipelined architecture to improve throughput, performs arctangent operation using vectoring mode of CORDIC algorithm. Fixed-point MATLAB modeling and simulations are carried out to determine the optimized bit-widths and number of iteration. Phase calculator designed in Verilog HDL is verified by emulating the restoration of virtual 3D data using MATLAB/Simulink and FPGA-in-the-loop verification.

• Proceedings of the Korean Information Science Society Conference
• /
• 2005.07a
• /
• pp.898-900
• /
• 2005

모듈러 멱승은 양수 x, E, N에 대하여 $x^Emod$ N로 정의된다. 모듈러 멱승 연산은 대부분의 공개키 암호화 알고리즘과 전자서명 프로토콜에서 핵심적인 연산으로 사용되고 있으므로, 그 효율성은 암호 프로토콜의 성능에 직접적인 영향을 미친다. 따라서 모듈러 멱승 연산에 필요한 곱셈 수를 감소시키기 위하여, 슬라이딩 윈도우를 적용한 CLNW 방법이나 VLNW 방법이 가장 널리 사용되고 있다. 본 논문에서는 조합론(combinatorics)에서 많이 응용되는 그래프 모델을 모듈러 멱승 연산에 적용할 수 있음을 보이고, 일반화된 그래프 모델을 통하여 VLNW 방법보다 더 적은 곱셈 수로 모듈러 멱승을 수행하는 방법을 설명한다. 본 논문이 제안하는 방법은 전체 곱셈 수를 감소시키는 새로운 블록들을 일반화된 그래프 모델의 초기 블록 테이블에 추가할 수 있는 초기 블록 테이블의 두 가지 확장 방법들로써, 접두사 블록의 확장과 덧셈 사슬 블록의 확장이다. 이 방법들은 새로운 블록을 초기 블록 테이블에 추가하기 위해 필요한 곱셈의 수와 추가한 뒤의 전체 곱셈 수를 비교하면서 초기 블록 테이블을 제한적으로 확장하므로, 지수 E에 non-zero bit가 많이 나타날수록 VLNW 방법에 비해 좋은 성능을 보이며 이는 실험을 통하여 검증하였다.

• The Journal of Korean Association of Computer Education
• /
• v.7 no.1
• /
• pp.55-66
• /
• 2004

The Internet today provides group communication model, multicast service. It is important to keep security for multicast communication. Member leaving is associated with scalability problem for group key management. If one member of the group is removed, new group key has to be changed and communicated to all remaining members of group. Modification and distribution of new group keys for rekeying is an expensive operation. Minimizing the number of messages and operation cost for generation of the composite keys are important evaluating criteria of multicast key management scheme. Periodic rekey helps reducing these important parameters rather than removing members sequentially in fashion one after another. In this paper, Hamming distance is calculated between every members to be removed. The members with Hamming distance less than threshold are selected for rekeying procedure. With running the round assignment algorithm, our model has advantages of reducing the number of message and operation cost for generation of the composite keys for rekeying.

• School Mathematics
• /
• v.5 no.2
• /
• pp.223-240
• /
• 2003

The purpose of this study was to investigate the preservice elementary teachers' knowledge of division through open-ended problems focused on the following perspectives in understanding division : connectedness between procedural and conceptual knowledge as well as the knowledge of units. Results indicates that the preservice elementary teachers showed low level of understanding of division such as the making word problem including division of fractions and the identification of the units in division operation.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2023.05a
• /
• pp.165-167
• /
• 2023

양자 컴퓨터는 기존의 클래식 컴퓨터와 달리 양자역학 원리를 활용해 정보 처리를 수행하며, 특정 문제들을 훨씬 빠르게 해결할 수 있다. 양자 컴퓨터는 큐빗을 기본 단위로 사용하고, 아다마르 게이트, CNOT 게이트, 파울리 게이트, 토플리 게이트 등을 조합하여 양자 회로를 구성한다. Toffoli 게이트는 유니버설 게이트 중 하나로, 세 개의 큐빗을 입력받아 조건부 (Controlled-Controlled) NOT 연산을 수행한다. 이 게이트는 복잡한 작업을 기본 양자 게이트로 분해할 수 있어, 회로의 게이트 수, 깊이 및 오류율 측면에서 최적화할 수 있다. 기본 양자 게이트 중 T 게이트는 노이즈와 오류에 영향을 받을 수 있으므로, T 게이트의 수와 깊이를 최적화하는 것이 중요하다. 본 논문은 Toffoli 게이트 분해를 통해 양자 회로의 게이트 수와 깊이를 최적화하는 방법을 조사한다.

• Journal of Elementary Mathematics Education in Korea
• /
• v.23 no.1
• /
• pp.143-168
• /
• 2019

Along with the significance of algebraic thinking in elementary school, it has been recently emphasized that the properties of number and operations need to be explored in a meaningful way rather than in an implicit way. Given this, the purpose of this study was to analyze how third graders could understand the properties of operations in multiplication after they were taught such properties through a reconstructed unit of multiplication. For this purpose, the students from three classes participated in this study and they completed pre-test and post-test of the properties of operations in multiplication. The results of this study showed that in the post-test most students were able to employ the associative property, commutative property, and distributive property of multiplication in (two digits) × (one digit) and were successful in applying such properties in (two digits) × (two digits). Some students also refined their explanation by generalizing computational properties. This paper closes with some implications on how to teach computational properties in elementary mathematics.

• Korean Journal of Childcare and Education
• /
• v.10 no.2
• /
• pp.175-192
• /
• 2014

The purpose of this study was to investigate the differences in perceived importance of mathematical education (perceived importance) and mathematical interaction of 5-year-olds' mothers according to contents of mathematical education. Second, we intended to examine whether mothers' understanding of purpose of mathematical education predicted on their perceived importance and mathematical interaction. Third, we analyzed relative influence between mothers' perceived effectiveness of concrete materials and worksheets on their perceived importance and mathematical interaction. The subjects consisted of 151 mothers of 5-year-olds lived in D city and K province in Korea. The results were as follows: First, mothers' perceived importance and mathematical interaction were higher in 'number and arithmetic'. Second, mothers' understanding of purpose of mathematical education predicted their perceived importance in all contents and mathematical interaction in 'number and arithmetic', 'geometry', and 'algebra'. Third, mothers' perceived effectiveness of concrete materials predicted better in most contents of mathematical education. Meanwhile, in 'number and operation', mothers' perceived effectiveness of worksheets did a predictive role in their importance awareness. These results were discussed in terms of necessity of a parent education program to provide practical information about contents and methods of mathematical education for their 5-year-old children.

• Journal of Elementary Mathematics Education in Korea
• /
• v.23 no.1
• /
• pp.19-41
• /
• 2019

In this study, we present an analysis framework based on the 2015 revised curriculum to analyze how mathematical contents and achievement standards for domains of numbers and computations have changed in the curriculum of elementary mathematics in Korea. Based on this, we classified the achievement standards by type and investigated their characteristics. The achievement standards for numbers and computations can be divided into the successive, the extinctive, and the additive achievement standards depending on their characteristics. The successive achievement standards are the ones that have consistently existed without being removed from the 1-st curriculum to the latest revision in 2015. The extinctive achievement standards are the ones that have been removed at some point during the revisions of nine times and do not remain in the current revision in 2015. The characteristics of the extinctive achievement standards were analyzed to be different before and after the 4-th curriculum. The additive achievement standards refer to the ones that have been newly added to the curriculum or that have been removed at a certain moment but added back in later and thus exist in the current revision in 2015. The characteristics of each type according to the changes of the achievement standards can be thought to be the results that the revision for the mathematics curriculum in Korea has been faithfully conducted. Based on the results of this study, we suggest some implications for organizing the achievement standards in the future curricular development.

• School Mathematics
• /
• v.10 no.4
• /
• pp.537-555
• /
• 2008

The study aims to analyze elementary school students' understanding of the concept of equality sign in contexts, to reflect the types of contexts for equality sign which mathematics textbook series for $1{\sim}4$ grades on natural numbers and its operation provide, and to invetigate the effects of teaching methods of the concept of equality sign suggested in this research. In order to achieve these purposes, the origin, concept, and contexts of equality sign were theoretically reviewed and organized. Also the error types in using equality sign were reflected. Modelling, discussing truth or falsity of equations, identifying relations between numbers and their operation, conjecturing basic properties of numbers and their operations, experiencing diverse contexts for equality sign, and creating contexts for equality sign are set up as teaching methods for better understanding the concept of equality sign. The conclusions are as follows. Firstly, elementary school students' under-standing of the concept of equality sign varied by context and was generally far from satisfactory. In particular, they had difficulties in understanding the concept of the equal sign in contexts with operations on both sides. The most frequently witnessed error was to recognize equality sign as a result of operations. Secondly, student' lack of understanding of the concept of equality sign came from the fact that elementary textbooks failed to provide diverse contexts for equality sign. According to the textbook analysis, contexts with operations on the left side of the equal sign in the form of $a{\pm}b=c$ were provided excessively, with the other contexts hardly seen. Thirdly, teaching methods provided in the study were found to be effective for enhancing understanding the concept of equality sign. In other words, these methods enabled students to focus on relational understanding of concept of equality sign rather than operational one.