• Journal of Industrial Technology
• /
• v.10
• /
• pp.73-76
• /
• 1990

본 논문은 대용량 주기억장치를 갖는 컴퓨터 상에서 효율적으로 수행 될 수 있는 외부 합병정렬 방법에 대하여 기술한다. 제시된 정렬 방법은 주기억 장치의 용량이 정렬될 화일 크기의 제곱근보다 크다는 조건하에서, 주기억 장치를 최대로 이용하여 외부 합병정렬에 소요되는 외부 합병의 횟수를 최소화 함으로써 외부 합병정렬의 성능에 가장 큰 영향을 미치는 입출력 시간을 크게 줄일수 있음을 보였다.

• Communications of Mathematical Education
• /
• v.13 no.2
• /
• pp.457-475
• /
• 2002

수학사를 통해 볼 때 눈금 없는 자와 컴퍼스를 이용한 작도 가능성의 문제는 여러 면에서 의미가 있었다. 종이 접기는 수학과는 무관하게 나름대로 많은 흥미를 끌어 왔다. 그러나 종이 접기가 기하학적 작도와 흥미 있는 관련이 있음이 알려지면서 수학적으로도 연구되었고 더 나아가 수학 학습에의 유의미한 활용 가능성이 제안되었다. 본 글에서는 종이 접기에서 괄목할 만한 수학적 성질을 고전적인 작도 가능성의 문제와 다항식의 거듭 제곱근에 의한 가해성 등과 관련하여 고찰한다. 또, 초 ${\cdot}$ 중등 학교에서 활용 가능한 가상의 수업 프로토콜도 제시한다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.7 no.3
• /
• pp.350-357
• /
• 2006

In this paper, a PSPICE model of piezoelectric transformer and CCFL using an electrical equivalent circuit was presented. The parameters of CCFL for PSPICE were derived by the least square method. The computer simulations were performed and the results are compared on the PSIPCE model of piezoelectric transformer driven by push-pull inverter and CCFL.

• Proceedings of the Korea Society of Elementary Mathematics Education
• /
• 2010.08a
• /
• pp.1-12
• /
• 2010

초등학교 6학년을 대상으로 6회 총 120분 동안 1996을 활용해서 1에서 100까지 수를 만들게 하는 활동을 한 결과를 제시하고 분석하였다. 이 퍼즐 과제 활동은 아이들의 수학적 사고를 많이 향상시켰으며, 수학적 성향을 강화시켰다. 특히, 이 과제에서 아이들은 협동의 이점을 알게 되었고 수학적 의사소통의 중요성도 경험하는 계기가 되었다. 무엇보다도 지수, 제곱근, 가우스 함수의 아이디어가 먼저 제시되고, 후속학습이 일어났다. 계산기가 어떻게 활용되어야 하는지에 대한 아이디어도 제공했다.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2009.10a
• /
• pp.142-143
• /
• 2009

Ar/$CH_4$ 마이크로웨이브 플라즈마 하에서 나노결정다이아몬드 박막의 미세구조 형성 과정에 대하여 연구하였다. 실리콘 기판 위에 불균일 핵생성을 위해 만든 스크래치 자리에 생성된 나노결정 크기의 다이아몬드 입자는 시간의 경과에 따라 성장하고 이웃하고 있는 입자들 간에 접촉이 일어나 표면을 완전히 채우게 되면 다이아몬드 박막이 형성되고 지속적인 박막 두께의 성장이 일어나게 된다. 입자들의 높이(혹은 직경)는 증착시간의 제곱근에 비례하는 것으로 나타났다.

• Journal of the Korean Data and Information Science Society
• /
• v.20 no.2
• /
• pp.349-356
• /
• 2009

In this study, we suggest the estimation method of the relative risk for the unemployment statistics of a small area such as si, gun, gu in Korea. The considered method are the usual pooled estimator, weighted estimator with the inverse of log-variance as weights, and the Jackknife estimator. And we compare with the efficiency of the three estimators by estimating the bias and mean square errors using real data from the 2002 Economically Active Population Survey of Gyeonggi-do. We compute the unemployed rate of male and female in small areas, and then estimate the common relative risk for the unemployed rate between male and female. Also, the stability and reliability of the three estimators for the common relative risk was evaluated using the RB(relative bias) and the RRMSE(relative root mean square error) of these estimators. Finally, the Jackknife estimator turned out to be much more efficient than the other estimators.

• Journal of the Korean Data and Information Science Society
• /
• v.27 no.6
• /
• pp.1443-1452
• /
• 2016

In this paper, we study a sample design for survey on goodwill in retail properties to provide a protecting policy for small traders and tenants, to use basic data for a dispute case related to goodwill. Since goodwill in retail properties is occurred by individual rent company, we use the census on establishments from the Statistics Korea as population. First of all, we consider preferentially seven metropolitan cities in which there are more than half of population. Total sample size is decided as 8,000. We allocate the sample size for markets as stratum in each city using proportional formula and the sample size for industrial classifications in each market using root proportional formula. Also we compute survey weights and calculate estimators, standard errors and interval of estimators for each characteristic such as type of establishments and market in seven metropolitan cities.

• The Korean Journal of Applied Statistics
• /
• v.20 no.2
• /
• pp.387-394
• /
• 2007

This paper considers several stratification strategies for multivariate and multipurpose survey with several quantitative stratification variables. We propose three methods of stratification based on, respectively, the method of cumulative frequency square root which is the most popular one in univariate stratification, cluster analysis, and factor analysis followed by cluster analysis. We then compare the efficiency of those methods using the Dong-Eup-Myun data of the holding numbers of farming machines, extracted from the 2001 Agricultural Census. It turned out that the method based on cluster analysis with factor analysis would be a relatively satisfactory strategy.

• Water for future
• /
• v.28 no.5
• /
• pp.219-233
• /
• 1995

A non-stationary multivariate model is selected in which the mean and variance of rainfall are not temporally or spatially constant. And the rainfall prediction system is constructed which uses the recursive estimation algorithm, Kalman filter, to estimate system states and parameters of rainfall model simulataneously. The on-line, real-time, multivariate short-term, rainfall prediction for multi-stations and lead-times is carried out through the estimation of non-stationary mean and variance by the storm counter method, the normalized residual covariance and rainfall speed. The results of rainfall prediction system model agree with those generated by non-stationary multivariate model. The longer the lead time is, the larger the root mean square error becomes and the further the model efficiency decreases form 1. Thus, the accuracy of the rainfall prediction decreases as the lead time gets longer. Also it shows that the mean obtained by storm counter method constitutes the most significant part of the rainfall structure.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.12
• /
• pp.2655-2663
• /
• 2011

Several algorithms have been developed to detect AF which rely either on the form of P waves or the based on the time frequency domain analysis of RR variability. However, locating the P wave fiducial point is very difficult because of the low amplitude of the P wave and the corruption by noise. Also, the time frequency domain analysis of RR variability has disadvantage to get the details of irregular RR interval rhythm. In this study, we describe an atrial fibrillation detection algorithm through non-linear analysis of irregular RR interval rhythm based on the variability, randomness and complexity. We employ a new statistical techniques root mean squares of successive differences(RMSSD), turning points ratio(TPR) and sample entropy(SpEn). The detection algorithm was tested using the optimal threshold on two databases, namely the MIT-BIH Atrial Fibrillation Database and the Arrhythmia Database. We have achieved a high sensitivity(Se:94.5%), specificity(Sp:96.2%) and Se(89.8%), Sp(89.62%) respectively.