• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.47.2-47
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• 2001

This paper is concerned with the limiting zeros, as the sampling period tends to zero, of a multivariable discrete-time system composed of an approximate fractional-order hold (AFROH), a continuous-time plant and a sampler in cascade. An approximate fractional-order hold is proposed to implement fractional-order hold (FROH) and is applied to instead of the zero-order hold (ZOH). The implementing problem of the fractional-order hold is overcome. The properties of the limiting zeros are studied and the location problem of them is solved. In addition, a stability condition of the zeros for sufficiently small sampling period is derived ...

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 1998년도 가을 학술발표논문집 Vol.25 No.2 (1)
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• pp.670-672
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• 1998

반복되는 형태의 문자열은 많은 분야에서 연구되고 있다. 반복적인 문자열 형태의 한 종류인 주기(period)는 주어진 문자열을 x라 할 때, x가 pn의 접두어(prefix)가 되는 p를 말한다. 본 논문에서는 근사주기(approximate period)의 개념을 제시하고, 길이가 각각 n, m인 두 문자열 x, p가 주어졌을 때, p가 x의 근사주기가 되는 최소의 오차를 O(m2n) 시간에 찾는 알고리즘을 제시한다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1999년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall
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• pp.170-177
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• 1999

The natural period calculation equations specified in the current building code are empirical formulas that depend on height and material type of the structure. Building with the upper wall and lower frame type is a unique structure which composed of two different structural system This type of structure needs either the deep transfer girder or the thick transfer plate that brings the sudden change of stiffness and mass. Therefore the natural period equations recommended by the current code can not be applied directly. In this study the natural period of building with typical plan obtained by dynamci analysis is compared with that of various codes. Ad approximate estimation equation for the natural period of building with the upper wall and lower frame type obtained by regression analysis is recommended. by the current code can not be applied directly. In this study the natural period of building with typical plan obtained by dynamic analysis is compared with that of various codes, And approximate estimation equation for the natural period of building with the upper wall and lower frame type obtained by regression analysis is recommended.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제2권2호
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• pp.119-122
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• 2013

주기와 같은 반복문자열에 대한 연구는 데이터압축, 컴퓨터활용 음악분석, 바이오인포매틱스 등 다양한 분야에서 진행되고 있다. 바이오인포매틱스 분야에서 주기는 유전자 서열이 반복적으로 나타나는 종렬중복과 밀접한 관련이 있으며 이는 근사문자열매칭을 이용한 근사주기 연구와 관련이 있다. 본 논문에서는 기존의 근사주기에 대한 정의를 보완하는 거리합기반 근사주기를 정의하고 이에 대한 연구 결과를 제시한다. 길이가 각각 m과 n인 문자열 p와 x가 주어졌을 때, p의 x에 대한 거리합기반 최소 근사주기거리를 가중편집거리에 대해 $O(mn^2)$ 시간, 편집거리에 대해 O)(mn) 시간, 해밍거리에 대해 O(n) 시간에 계산하는 알고리즘을 제시한다.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제16권6호
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• pp.742-746
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• 2010

기존의 패턴 매칭을 이용한 랜덤성 테스트를 개선하기 위하여, 근사 주기에 기반한 새로운 랜덤성 테스트를 제안한다. 근사 주기를 활용하면 랜덤수열에서 비슷한 부분이 반복되는 것을 찾아낼 수 있지만, 계산 시간이 오래 걸리는 단점이 있다. 본 논문에서는 근사주기를 계산하는 시간복잡도를 O($n^3$)에서 O($n^2$)으로 줄임으로써, O($n^2$)의 시간복잡도를 가지는 새로운 랜덤성 테스트를 제안한다. 그리고 AES 암호알고리즘을 이용한 의사 랜덤수열(pseudo random number)과 실제 랜덤수열(true random number)에 제안한 테스트를 적용하여 실험하였다.

• Structural Engineering and Mechanics
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• 제25권6호
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• pp.717-732
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• 2007

A formula to approximate the fundamental period of a fixed-free mass-spring system with varying mass and varying stiffness is formulated. The formula is derived mainly by taking the dominant parts from the general form of the characteristic polynomial, and adjusting the initial approximation by a coefficient derived from the exact solution of a uniform case. The formula is tested for a large number of randomly generated structures, and the results show that the approximated fundamental periods are within the error range of 4% with 90% of confidence. Also, the error is shown to be normally distributed with zero mean, and the width of the distribution (as measured by the standard deviation) tends to decrease as the total number of discretized elements in the system increases. Other possible extensions of the formula are discussed, including an extension to a continuous cantilever structure with distributed mass and stiffness. The suggested formula provides an efficient way to estimate the fundamental period of building structures and other systems that can be modeled as mass-spring systems.

• 한국경영과학회지
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• 제22권2호
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• pp.125-137
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• 1997

We are concerned with the packing policy determines the optimal packing of products with variable sizes to minimize the penalty costs for idle space and product spliting. Optimal packing problem is closely related to the optimal packet/record sizing problem in that randomly generated data stream with variable bytes are divided into a unit of packet/record for transmitting or storing. Assuming the product size and the production period are independently determined by renewal process, we can approximate the renewal process and formulate the optimization problem that minimize the expected packing cost for a production period. The problem is divided into two cases according to whether a product is allowed to split or not. Computational results for various distributions will be given to verify the approximation procedure and the resulting optimization problem.

• 응용통계연구
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• 제22권3호
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• pp.607-616
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• 2009

In many epidemiological studies, the occurrence times of the event of interest are right-censored or interval censored. In certain situations such as the AIDS data, however, the incubation period which is the time between HIV infection and the diagnosis of AIDS is usually doubly censored. In this paper, we impute the interval censored HIV infection time using three imputation methods. Mid imputation, conditional mean imputation and approximate Bayesian bootstrap are implemented to obtain right censored data, and then Gibbs sampler is used to estimate the coefficient factor of the incubation period. By using Bayesian approach, flexible modeling and the use of prior information is available. We applied both parametric and semi-parametric methods for estimating the effect of the covariate and compared the imputation results incorporating prior information for the covariate effects.

• 대한조선학회지
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• 제23권3호
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• pp.10-16
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• 1986

This paper deals with a simple, approximate formula to predict the natural frequencies of the sagged cable structures. Assuming that the propagation velocity of the lateral wave is dependent only on the local mass per unit length and local tension, the explicit simple formula to predict the fundamental period is newly derived. The modified form of these formula is also presented for the prediction of the fundamental period of general shaped cable structures. The results of comparison shows fairly good agreements with experimental results and with theoretical ones. This formula is also used to predict the natural frequencies of a long vertical cable and the derived approximate formula in that case, becomes identical to the exact solution.

• 대한한의학원전학회지
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• 제22권2호
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• pp.275-283
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• 2009

The "Naegyeongseupyubangron(內經拾遺方論)", written by Nakyonggil(駱龍吉), is an ancient book of Bangron(方論). The exact time period of this book is unknown. To estimate its written time, we compared the contents of this book to other sources on the cause of diseases, the description of symptoms, the transmission of diseases, and treatments. In addition, we analyzed the features of the book by comparing it to other books of Bangron(方論). As a result, we estimated the approximate time period that it was written and gained a better understanding of the ancient medicine. We reached several conclusions through this study. 1. The approximate time period of "Naegyeongseupyubangron(內經拾遺方論)" is that of the Southern Song(南宋) dynasty of China, probably after "Saminbang(三因方)" between 1174 and 1279. 2. Nakyonggil(駱龍吉) was influenced by Wangbing(王冰), Sonsamak(孫思邈), Yuhagan(劉河間), Jinmutaek(陳無擇). and he influenced "Uibanggo(醫方考)". 3. The "Naegyeongseupyubangron(內經拾遺方論)" is the most comprehensive book among the books of Bangron(方論) because of its analysis of the "Hwangjenaegyeong(黃帝內經)" and its connection to the treatment of ancient diseases in Oriental Medical History.