• Journal of the Korea Computer Industry Society
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• v.5 no.1
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• pp.1-8
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• 2004

As more and more information is processed and stored in the digital form, many techniques and systems have been developed for service multimedia informations in wireless internet. In this paper, we propose MSPOB(Multimedia Statistics Post Office Box) structure for service datum which are related with similarity to subject a set of documents through grouping. The proposed structure is determined by relationship of datum based on count index and inverted file and is determined it through the semantic similarity between objects

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.5
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• pp.785-790
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• 2008

A technique for determining the feedback gain of the states feedback controller using a real-coded genetic algorithm(RCGA) is presented. It is concerned with the states error to the performance index of a RCGA. As for assessing the performance of the controller three performance criteria (ISE. IAE and ITAE) are adopted. And designing the controller involves a constrained optimization problem. Therefore a real-coded genetic algorithm incorporating the penalty strategy is used. The performance of the proposed method is demonstrated through a set of simulation about an inverted pendulum system.

• Proceedings of the Korean Information Science Society Conference
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• 2008.06c
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• pp.248-251
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• 2008

문서 표절이 사회적으로 이슈가 됨에 따라 표절 문서를 판별할 수 있는 시스템의 필요성이 대두되었다. 문서 표절 검사 시스템에서 가장 중요한 이슈는 성능과 속도인데 이 두 가지를 모두 만족시키기 위해서는 표절을 상세하게 검사하기 전에 표절 의심 문서에 대한 비교 문서군이 크기를 최적화하여 표절 검사 범위를 최대한 작게 만들어야 한다. 비교 문서군의 크기를 최적화하기 위해서는 표절 의심 문서와 상관이 없는 문서를 필터링 하는 작업이 필요하다. 이 논문에서는 문서를 빠르게 필터링 하기 위해서 웹 문서 검색에 사용되는 Inverted Index을 이용하여 적당한 시간 안에 비교 문서군의 크기를 최적화 하는 방법들을 알아보고 각각의 방법들의 성능을 비교 분석하는 방법을 제시하며 그 방법들을 바탕으로 성능을 분석하여 최적화된 문서 필터링 방법을 알아본다.

• Journal of Computing Science and Engineering
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• v.11 no.1
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• pp.1-8
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• 2017

Naive Bayes nearest neighbor (NBNN) is a simple image classifier based on identifying nearest neighbors. NBNN uses original image descriptors (e.g., SIFTs) without vector quantization for preserving the discriminative power of descriptors and has a powerful generalization characteristic. However, it has a distinct disadvantage. Its memory requirement can be prohibitively high while processing a large amount of data. To deal with this problem, we apply a spherical hashing binary code embedding technique, to compactly encode data without significantly losing classification accuracy. We also propose using an inverted index to identify nearest neighbors among binarized image descriptors. To demonstrate the benefits of our method, we apply our method to two existing NBNN techniques with an image dataset. By using 64 bit length, we are able to reduce memory 16 times with higher runtime performance and no significant loss of classification accuracy. This result is achieved by our compact encoding scheme for image descriptors without losing much information from original image descriptors.

• Journal of Information Processing Systems
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• v.13 no.4
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• pp.863-875
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• 2017

The traditional text similarity measurement methods based on word frequency vector ignore the semantic relationships between words, which has become the obstacle to text similarity calculation, together with the high-dimensionality and sparsity of document vector. To address the problems, the improved singular value decomposition is used to reduce dimensionality and remove noises of the text representation model. The optimal number of singular values is analyzed and the semantic relevance between words can be calculated in constructed semantic space. An inverted index construction algorithm and the similarity definitions between vectors are proposed to calculate the similarity between two documents on the semantic level. The experimental results on benchmark corpus demonstrate that the proposed method promotes the evaluation metrics of F-measure.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.05a
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• pp.357-359
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• 2019

RDBMS 상에서 문서에 포함된 키워드 검색을 위한 질의 시 병합 조인 방식을 통해 키워드 검색을 시도하게 된다. 그러나 대용량의 문서를 저장하고 있는 RDBMS 내에서 병합 조인을 사용 시 검색 키워드에 대해 불필요한 비교 연산으로 인하여 질의 문에 대한 검색시간이 길어질 수 있다. 본 논문은 행 지향 관계형 역 색인을 이용하여 키워드 검색 질의 시 병합 조인의 단점을 보완한 지그재그 병합 조인 알고리즘을 사용한다. 관계형 데이터베이스인 postgreSQL 에서 프로시저로 불필요한 비교 연산을 최소화한 지그재그 병합 조인 알고리즘을 구현하여 키워드 검색에 대한 질의 속도 향상을 확인하였다.

• Journal of Information Processing Systems
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• v.4 no.1
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• pp.17-26
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• 2008

This research proposes a new strategy where documents are encoded into string vectors and modified version of KNN to be adaptable to string vectors for text categorization. Traditionally, when KNN are used for pattern classification, raw data should be encoded into numerical vectors. This encoding may be difficult, depending on a given application area of pattern classification. For example, in text categorization, encoding full texts given as raw data into numerical vectors leads to two main problems: huge dimensionality and sparse distribution. In this research, we encode full texts into string vectors, and modify the supervised learning algorithms adaptable to string vectors for text categorization.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.1230-1232
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• 2015

소셜 네트워크 서비스(SNS)로 인해 스트리밍 환경에서 발생되는 데이터들이 급격하게 증가하고 있다. 이러한 많은 데이터 사이에서 특정 키워드를 담고 있는 문서를 찾고자 한다. 문서를 찾는 대표적인 색인인 역색인을 사용한다. 그러나 데이터가 증가하게 되면 데이터를 참조하는 색인의 크기 또한 증가한다. 결국 데이터뿐만 아니라 색인 또한 디스크에 저장되어야 한다. 본 논문에서는 역색인을 지수적으로 증가시키면서 관리하는 방법을 다룬다. 새로운 문서는 가장 작은 역색인에 저장이 되고, 후에 더 큰 역색인으로 옮겨지게 된다. 매번 전체 역색인을 읽지 않고 작은 역색인을 갱신함으로서 갱신부하를 줄이게 된다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.5
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• pp.533-541
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• 2021

Retaining walls have been used to prevent slope failure through resistance of earth pressure in railway, road, nuclear power plant, dam, and river infrastructure. To calculate dynamic earth pressure and determine the characteristics for seismic behavior, many researchers have analyzed the nonlinear response of ground and structure based on various numerical analyses (FLAC, PLAXIS, ABAQUS etc). In addition, seismic fragility evaluation is performed to ensure safety against earthquakes for structures. In this study, we used the FLAC2D program to understand the seismic response of the inverted T-type wall with a backfill slope, and evaluated seismic fragility based on relative horizontal displacements of the wall. Nonlinear site response analysis was performed for each site (S2 and S4) using the seven ground motions to calculate various seismic loadings reflecting site characteristics. The numerical model was validated based on other numerical models, experiment results, and generalized formula for dynamic active earth pressure. We also determined the damage state and damage index based on the height of retaining wall, and developed the seismic fragility curves. The damage probabilities of the retaining wall for the S4 site were computed to be larger than those for the S2 site.

• Korean Journal of Optics and Photonics
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• v.8 no.4
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• pp.277-282
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• 1997

The complex refractive index of Diamond-like Carbon (DLC) thin films, which can be applied to optical devices or electrical devices, have been determined using optical methods. DLC thin films are grown on Si(100) substrates and vitreous silica substrates respectively, using the technique of plasma enhanced chemical vapor deposition (PECVD). The spectroscopic ellipsometry data($\psi$, $\Delta$) and the transmission spectra of these DLC films are obtained. These optical spectra are analyzed with the help of the Sellmeier dipersion relation and a quantum mechanically derived dispersion relation. Using spectroscopic ellipsometry data at their transparent region, the refractive index and the effective thickness of DLC films on vitreous silica are model calculated, Then the transmission spectra are inverted to yield the extinction coefficient spectra k(λ) at absorbing region. These spectra are fit to the quantum mechanical dispersion relation and the best fit dispersion constants are determined. The complex refractive indices are easily calculated with these constants. The spectroscopic ellipsometry data at the absorbing region in model calculated to give the packing densities and the degrees of surface microroughness of DLC films. Discussions are made in correlation with the growth condition of DLC films.