• 음성과학
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• 제8권2호
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• pp.181-191
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• 2001

The acoustic quality of a vowel is known to be mostly determined by the frequencies of the first formant(Fl) and the second formant(F2). The perceptual(or psychological) dimensions of vowel perception were examined in this study. Also the relationships among perceptual dimensions, acoustical dimensions(Fl & F2), and articulatory gestures of vowel were discussed. Using multi-dimensional scaling(MDS) technique, the experiment was performed in order to identify the perceptual dimensions of the perception of Korean vowel. In the experiment 8 Seoul standard speakers performed the similarity rating task of 10 synthesized Korean vowels. Two-dimensional MDS solution based. on the similarity rating scores was obtained. The results showed that two perceptual dimensions, D1 and D2 were correlated strongly with F2 and F1(r = -.895 and .878 respectively), and were so interpreted as 'vowel advancement' and 'vowel height' respectively. The relationship between the perceptual dimensions of vowel and the articulatory positions of tongue suggested that perception may be directly linked to production. Further research problems were discussed in the .final section.

• Bulletin of the Korean Chemical Society
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• 제32권7호
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• pp.2433-2442
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• 2011

The three dimensional quantitative structure activity relationship (3D QSAR) models were developed using Comparative molecular field analysis (CoMFA), comparative molecular similarity indices analysis (CoMSIA) and docking studies. The fit of Quinazolinone antifolates inside the active site of modeled bovine dihydrofolate reductase (DHFR) was assessed. Both ligand based (LB) and receptor based (RB) QSAR models were generated, these models showed good internal and external statistical reliability that is evident from the $q^2_{loo}$, $r^2_{ncv}$ and $r^2_{pred}$. The identified key features enabled us to design new Quinazolinone analogues as DHFR inhibitors. This study is a building bridge between docking studies of homology modeled bovine DHFR protein as well as ligand and target based 3D QSAR techniques of CoMFA and CoMSIA approaches.

• 한국해양공학회지
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• 제23권4호
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• pp.32-37
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• 2009

An analytic similarity shape solution was studied for a two-dimensional floating and fluid-filled membrane structure. The static shape of a membrane structure can be expressed as a set of nonlinear ordinary differential equations. The integration of curvature leads to an analytic solution for the shape, which contains unknown boundary values. Matching the upper and lower shapes at the free surface incorporated with their buoyancy allowed the unknowns to be determined. Some characteristic values of similarity shapes were evaluated and shapes are illustrated for various density ratios and volume efficiency ratios.

• 산업경영시스템학회지
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• 제24권65호
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• pp.41-50
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• 2001

Clustering in data mining is a discovery process that groups a set of data such that the intracluster similarity is maximized and intercluster similarity is minimized. The discovered clusters from clustering process are used to explain the characteristics of the data distribution. In this paper we propose a new methodology for clustering related transactions with categorical attributes. Our approach starts with transforming general relational databases into a transactional databases. We make use of inter-dimensional association rules for composing hypergraph edges, and a hypergraph partitioning algorithm for clustering the values of attributes. The clusters of the values of attributes are used to find the clusters of transactions. The suggested procedure can enhance the interpretation of resulting clusters with allocated attribute values.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.221-223
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• 2010

Considering the similarity between fluid vortex and arrhythmogenic reentrant waves in heart, we applied the non-dimensionalization method in fluid dynamics to arrhythmia analysis and discovered a new non-dimensional simulation results, there was a threshold value of the number that resulted in the induction of a reentrant wave.

• 한국지능시스템학회논문지
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• 제19권4호
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• pp.556-561
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• 2009

In this paper, we propose new method to calculate the distance between intuitionistic fuzzy sets(IFSs) based on the three dimensional representation of IFSs and analyze the relations of similarity measure and distance measure of IFSs. Finally, we apply the proposed measures to pattern recognitions.

• 정보처리학회논문지D
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• 제11D권2호
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• pp.269-280
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• 2004

피라미드 기법은 n-차원 공간 데이터를 1차원 데이터로 변환하여 B+-트리로 표현하며, n-차원 데이터 공간에서 하이퍼큐브 영역질의 처리로 발생하는 “차원의 저주현상”에 영향을 받지 않게 검색 시간 문제를 해결하고 있다. 또 구형 피라미드 기법(SPY-TEC)은 피라미드 기법의 공간 분할 전략을 응용하여 유사도 검색에 적합한 구 영역질의 방법을 사용하고 검색 성능을 개선하고 있다. 하지만 유사도 검색의 응용에서 영역질의는 범위를 지정하는데 어려움이 있어 최근접 질의가 더 효율적이며, 기존의 제안된 인덱스 기법들은 특정 분포의 데이터에 대해서만 우수한 성능을 보이는 단점이 있다. 따라서 이 논문에서는 멀티미디어 데이터와 같은 고차원 데이터의 검색 성능을 향상시키기 위해 제안되었던 PdR-트리를 이용하여 최근접 객체 검색 기법을 제안한다. 다양한 분포의 모의 데이터와 실제 데이터를 이용하여 실험한 결과, PdR-트리가 피라미드 기법과 구형 피라미드 기법보다 검색 성능이 향상되었음을 보이고 있다.

• 한국정보과학회논문지:데이타베이스
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• 제37권2호
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• pp.71-81
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• 2010

데이터의 군집을 찾아내는 문제는 패턴 인식, 이미지 처리, 시장 조사 등 많은 응용 분야에서 널리 사용되고 있다. 군집의 질을 결정하는 핵심 요소로는 유사 측도, 차원의 개수 등이 있다. 유사 측도는 데이터의 특성을 반영하여 다르게 정의되어야 하는데, 대부분 기존의 연구들은 데이터를 특징 지어주는 속성이 수치형으로 주어진 경우에 국한되어 있었다. 속성이 범주형으로 주어진 경우도 실생활에 많이 존재하지만, 범주형 변수에 대한 속성값의 유사성은 값의 순서가 고유하게 정해지지 않아서 정의하기 어렵다. 이에 더하여, 고차원 데이터에 대해서는 데이터 점들이 희박하게 위치하여 가까운 점과 먼 점간의 차이가 거의 없고, 군집화 결과가 좋지 않을 수 있다. 이 문제를 해결하기 위해 부분 차원 군집화 방법이 제안되어 왔다. 부분 차원 군집화 방법은 각 군집을 발견하기에 적합한 부분 차원을 선택하면서 군집화를 수행하는 방법이다. 본 논문에서는 범주형 속성으로 특징지어진 고차원 데이터를 부분 차원 군집화하기 위한 새로운 유사 측도를 제안한다. 유사 측도는 각 군집은 다른 군집과 구별되는 특정 정보를 잘 표현할 수 있어야 한다는 기본적인 가정 하에 속성들 사이의 상관성을 반영하여 정의되었다. 이들 모두를 반영한 유사측도는 기존에 존재하지 않았다는 점에서 본 연구는 의미가 있다. 실제 데이터 집합을 군집화하는 실험을 통해 제안하는 방법이 다른 군집화 방법보다 저차원 데이터와 고차원 데이터 모두에 대해 좀 더 정확한 군집 결과를 얻을 수 있음을 보였다.

• 한국수소및신에너지학회논문집
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• 제26권4호
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• pp.386-392
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• 2015

Flow characteristics inside a 10 inch ball valve have been analyzed using three-dimensional numerical analysis and experiments. Continuity and three-dimensional Reynolds-averaged Navier-Stokes equations have been used as governing equations for the numerical analysis. The numerical model has been constructed through the grid dependency test and validation with the results of experiments to ensure reliability and numerical effectiveness. The shear stress transport (SST) model has been used as the turbulence closure. The experimental test-rig has been constructed to measure pressure, temperature and flow rate along the pipeline. Some valve opening angles have been tested to evaluate the flow characteristics inside the ball valve and pipeline. The results show that the rapid pressure variations is observed while the valve opening angle decreases, which caused by flow separation at the downstream of the ball valve.

• International Journal of Computer Science & Network Security
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• 제24권5호
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• pp.79-88
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• 2024

The information retrieval domain deals with the retrieval of unstructured data such as text documents. Searching documents is a main component of the modern information retrieval system. Locality Sensitive Hashing (LSH) is one of the most popular methods used in searching for documents in a high-dimensional space. The main benefit of LSH is its theoretical guarantee of query accuracy in a multi-dimensional space. More enhancement can be achieved to LSH by adding a bit to its steps. In this paper, a new Dynamic Locality Sensitive Hashing (DLSH) algorithm is proposed as an improved version of the LSH algorithm, which relies on employing the hierarchal selection of LSH parameters (number of bands, number of shingles, and number of permutation lists) based on the similarity achieved by the algorithm to optimize searching accuracy and increasing its score. Using several tampered file structures, the technique was applied, and the performance is evaluated. In some circumstances, the accuracy of matching with DLSH exceeds 95% with the optimal parameter value selected for the number of bands, the number of shingles, and the number of permutations lists of the DLSH algorithm. The result makes DLSH algorithm suitable to be applied in many critical applications that depend on accurate searching such as forensics technology.