• 대한수학회보
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• 제58권2호
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• pp.433-444
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• 2021

In this paper a new generating procedure of a random chord is presented. This problem has its roots in the Bertrand's paradox. A study of the limit behaviour of its maximum length and the rate of convergence is conducted. In addition, moments of record values of random chord length are obtained for this case, as well as other cases of solutions of Bertrand's paradox.

• Nuclear Engineering and Technology
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• 제47권5호
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• pp.546-558
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• 2015

Chord length sampling method in Monte Carlo simulations is a method used to model spherical particles with random sampling technique in a stochastic media. It has received attention due to the high calculation efficiency as well as user convenience; however, a technical issue regarding boundary effect has been noted. In this study, after analyzing the distribution characteristics of spherical particles using an explicit method, an alternative chord length sampling method is proposed. In addition, for modeling in finite media, a correction method of the boundary effect is proposed. Using the proposed method, sample probability distributions and relative errors were estimated and compared with those calculated by the explicit method. The results show that the reconstruction ability and modeling accuracy of the particle probability distribution with the proposed method were considerably high. Also, from the local packing fraction results, the proposed method can successfully solve the boundary effect problem. It is expected that the proposed method can contribute to the increasing of the modeling accuracy in stochastic media.

• 한국정보과학회논문지:정보통신
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• 제36권2호
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• pp.80-89
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• 2009

분산 해쉬 테이블(DHT : Distributed Hash Table) 기반의 P2P는 기존 Unstructured P2P 방식의 단점을 보완하기 위한 방식이다. DHT 알고리즘을 사용하면 빠른 데이터 검색을 할 수 있고, 피어 개수에 무관하게 검색 효율을 유지할 수 있다. DHT 방식의 피어들은 카우팅 테이블을 최신으로 유지하기 위해 주기적으로 메시지를 보낸다. 모바일 환경의 경우, DHT 방식의 피어들은 라우팅 테이블을 최신으로 유지하고 요청 실패를 줄이기 위해서 빠른 주기로 메시지를 보내야 한다. 하지만 이로 인해, 전체 네트워크의 트래픽은 증가하게 된다. 본 논문에서는 리액티브 라우팅 테이블 업데이트 방식을 이용하여 기존 DHT에서의 라우팅 테이블 업데이트에 따른 부하를 줄이는 기법을 제안한다. 주기적으로 자신의 라우팅 테이블을 업 데이트하는 기존 방식(Proactive)과 달리, 제안된 방식에서는 데이터 요청이 들어 왔을 때만 라우팅 테이블을 업데이트하는 방식(Reactive)을 사용한다. 제안된 방식은 버클리 대학에서 만들어진 Chord 시뮬레이터(I3)를 이용하여 실험을 수행하였다. 실험을 통하여 제안된 방식이 기존 방식에 비해 성능이 향상되었음을 확인하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(II)
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• pp.1086-1093
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• 2002

In Korea mid chord offset method has been used to measure the track irregularities. This method has been also used all over the world widely because of its accessibility and the operational excellence for measured data. But it has been pointed out recently that track irregularities reconstructed from measured data have unexpected noise in the high frequency area as the defect of this way. This study shows the cause of noise which occurs during reconstructing process and mentions the solutions briefly.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2015년도 춘계 종합학술대회 논문집
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• pp.53-54
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• 2015

Optical music recognition (OMR) systems have been developed in recent years. However, chord symbols that play a role in a music sheet have been still disregarded. Therefore, we aimed to develop a proper approach to recognize these chord symbols. First, we divide the image of chord symbol into small segments in horizontal by a method based on vertical projection. Then, the optimal combination of these segments is found by using a lexicon-driven word scoring technique and a nearest neighbor classifier. The word that corresponds to the optimal combination is the result of recognition. The experiment gives an impressive result with accuracy 97.32%.

• 디지털콘텐츠학회 논문지
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• 제5권3호
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• pp.245-249
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• 2004

본 논문은 기존의 코드작곡 프로그램을 신경망 역 전파 방법을 통해 재구성 하였다. 대중성을 인정받은 기존의 대중가요들의 코드진행을 기대치로 부여하고 역전파 학습방법을 통해 그 기대치에 상웅하는 결과 값을 학습시켰다. 가중치 값을 변화시켜가면서 작곡 프로그램을 구현함으로써 기존의 작곡 방법을 더욱 유연하게 대중성의 코드진행 패턴에 가까운 결과를 낼 수 있도록 하였다.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2008년도 학술대회 1부
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• pp.739-743
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• 2008

본 연구에서는 사용자가 입력한 멜로디에 따른 반주 음악을 자동으로 생성하는 방법을 제시한다. 시작되는 코드는 사용자의 멜로디에 의해서 생성이 되며, 그 다음 코드들은 코드들간의 전이확률이 정의되어있는 마르코프 체인(markov chain)의 확률 테이블을 이용하여 연속적으로 생성된다. 확률 테이블은 기존 음악의 샘플 데이터를 강화학습(reinforcement learning)을 이용하여 학습된다. 또한 실시간으로 재생되는 반주 코드는 매 상태 마다 주어지는 보상 값을 통해 더 나은 행동을 취할 수 있도록 학습해 나간다. 멜로디와 각 코드들간의 유사성은 피치 클래스 히스토그램을 이용하여 계산된다. 본 기술을 사용하여 주어진 사용자 입력에 조화로운 반주 코드의 자동 생성이 가능하다.

• Steel and Composite Structures
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• 제21권2호
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• pp.323-342
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• 2016

To study the effect of collar-plate reinforcement on the static strength of tubular T-joints under axial loading, fundamental research work is carried out from both experimental test and finite element (FE) simulation. Through experimental tests on 7 collar-plate reinforced and 7 corresponding un-reinforced tubular T-joints under axial loading, the reinforcing efficiency is investigated. Thereafter, the static strengths of the above 14 models are analyzed by using FE method, and it is found that the numerical results agree reasonably well with the experimental data to prove the accuracy of the presented FE model. Additionally, a parametric study is conducted to analyze the effect of some geometrical parameters, i.e., the brace-to-chord diameter ratio ${\beta}$, the chord diameter-to-chord wall thickness ratio $2{\gamma}$, collar-plate thickness to chord wall thickness ratio ${\tau}_c$, and collar-plate length to brace diameter ratio $l_c/d_1$, on the static strength of a tubular T-joint. The parametric study shows that the static strength can be greatly improved by increasing the collar-plate thickness to chord wall thickness ratio ${\tau}_c$ and the collar-plate length to brace diameter ratio $l_c/d_1$. Based on the numerical results, parametric equations are obtained from curving fitting technique to estimate the static strength of a tubular T-joint with collar-plate reinforcement under axial loading, and the accuracy of these equations is also evaluated from error analysis.

• International Journal of Contents
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• 제12권4호
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• pp.53-61
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• 2016

Although extensively developed, optical music recognition systems have mostly focused on musical symbols (notes, rests, etc.), while disregarding the chord symbols. The process becomes difficult when the images are distorted or slurred, although this can be resolved using optical character recognition systems. Moreover, the appearance of outliers (lyrics, dynamics, etc.) increases the complexity of the chord recognition. Therefore, we propose a new approach addressing these issues. After binarization, un-distortion, and stave and lyric removal of a musical image, a rule-based method is applied to detect the potential regions of chord symbols. Next, a lexicon-driven approach is used to optimally and simultaneously separate and recognize characters. The score that is returned from the recognition process is used to detect the outliers. The effectiveness of our system is demonstrated through impressive accuracy of experimental results on two datasets having a variety of resolutions.

• 한국정밀공학회지
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• 제22권5호
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• pp.45-54
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• 2005

The purpose of this research is to find a simple and accurate NURBS interpolator for CNC systems such as robot, CMM and CNC machine tools. This paper presents a new design of NURBS interpolator for CNC system. The proposed algorithm used the recursive characteristics of NURBS equation, the previous incremental value and chord length for the sake of a constant chord length. Simulation study was conducted to see the performance of the proposed interpolator with reference-word and reference-pulse method. Consequently, an accurate and simple NURBS interpolator was possible for modem CNC systems.