• 정보기술과데이타베이스저널
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• 제3권2호
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• pp.75-96
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• 1996

This study is intended to compare the effectiveness of the neural network inductive learning model with a vector space model in information retrieval. As a result, searches responding to incomplete queries in the neural network inductive learning model produced a higher precision and recall as compared with searches responding to complete queries in the vector space model. The results show that the hybrid methodology of integrating an inductive learning technique with the neural network model can help solve information retrieval problems that are the results of inconsistent indexing and incomplete queries--problems that have plagued information retrieval effectiveness.

• Journal of Computing Science and Engineering
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• 제9권2호
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• pp.73-82
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• 2015

Understanding how the topic evolves is an important and challenging task. A topic usually consists of multiple related events, and the accurate identification of event evolution relationship plays an important role in topic evolution analysis. Existing research has used the traditional vector space model to represent the event, which cannot be used to accurately compute the semantic similarity between events. This has led to poor performance in identifying event evolution relationship. This paper suggests constructing a semantic aspect-based vector space model to represent the event: First, use hierarchical Dirichlet process to mine the semantic aspects. Then, construct a semantic aspect-based vector space model according to these aspects. Finally, represent each event as a point and measure the semantic relatedness between events in the space. According to our evaluation experiments, the performance of our proposed technique is promising and significantly outperforms the baseline methods.

• 전력전자학회논문지
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• 제22권1호
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• pp.18-26
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• 2017

This paper proposes the model predictive control with space vector modulation (SVM) method for current control of voltage-source inverter. Unlike the conventional method using a limited number of voltage vectors by switching states, the proposed method can consider various voltage vectors to identify the optimized voltage vector. The various voltage vectors are obtained by subdividing existing voltage vectors. The optimized voltage vector that minimizes the cost function is selected and applied to the inverter by using the SVM. The various voltage vectors and SVM reduce current ripples in the output AC side of the inverter compared with the conventional method. The effectiveness and performance of the proposed method are verified through simulation and experiment with a three-phase two-level voltage-source grid-connected inverter.

• Journal of Multimedia Information System
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• 제9권2호
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• pp.93-102
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• 2022

Dependency parsing is a decision problem of the syntactic relation between words in a sentence. Recently, deep learning models are used for dependency parsing based on the word representations in a continuous vector space. However, it causes a mislabeled tagging problem for the proper nouns that rarely appear in the training corpus because it is difficult to express out-of-vocabulary (OOV) words in a continuous vector space. To solve the OOV problem in dependency parsing, we explored the proper noun embedding method according to the embedding unit. Before representing words in a continuous vector space, we replace the proper nouns with a special token and train them for the contextual features by using the multi-layer bidirectional LSTM. Two models of the syllable-based and morpheme-based unit are proposed for proper noun embedding and the performance of the dependency parsing is more improved in the ensemble model than each syllable and morpheme embedding model. The experimental results showed that our ensemble model improved 1.69%p in UAS and 2.17%p in LAS than the same arc-eager approach-based Malt parser.

• 한국환경과학회지
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• 제3권4호
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• pp.349-356
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• 1994

The purpose of this study is to develop a linear reservoir model with Kalman filter using Kalman filter theory which removes a physical uncertainty of :ainfall-runoff process. A linear reservoir model, which is the basic model of Kalman filter, is used to calculate runoff from rainfall in river basin. A linear reservoir model with Kalman filter is composed of a state-space model using a system model and a observation model. The state-vector of system model in linear. The average value of the ordinate of IUH for a linear reservoir model with Kalman filter is used as the initial value of state-vector. A .linear reservoir model with Kalman filter shows better results than those by linear reserevoir model, and decreases a physical uncertainty of rainfall-runoff process in river basin.

• 인지과학
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• 제23권3호
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• pp.295-322
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• 2012

본 연구에서는 벡터 공간 모델과 HAL (Hyperspace Analog to Language)을 적용해서 단어 의미 유사성을 군집한다. 일정한 크기의 문맥을 통해서 단어 간의 상관성을 측정하는 HAL을 도입하고(Lund and Burgess 1996), 상관성 측정에서 고빈도와 저빈도에 다르게 측정되는 왜곡을 줄이기 위해서 벡터 공간 모델을 적용해서 단어 쌍의 코사인 유사도를 측정하였다(Salton et al. 1975, Widdows 2004). HAL과 벡터 공간 모델로 만들어지는 공간은 다차원이므로, 차원을 축소하기 위해서 PCA (Principal Component Analysis)와 SVD (Singular Value Decomposition)를 적용하였다. 유사성 군집을 위해서 비감독 방식과 감독 방식을 적용하였는데, 비감독 방식에는 클러스터링을 감독 방식에는 SVM (Support Vector Machine), 나이브 베이즈 구분자(Naive Bayes Classifier), 최대 엔트로피(Maximum Entropy) 방식을 적용하였다. 이 연구는 언어학적 측면에서 Harris (1954), Firth (1957)의 분포 가설(Distributional Hypothesis)을 활용한 의미 유사도를 측정하였으며, 심리언어학적 측면에서 의미 기억을 설명하기 위한 모델로 벡터 공간 모델과 HAL을 결합하였으며, 전산적 언어 처리 관점에서 기계학습 방식 중 감독 기반과 비감독 기반을 적용하였다.

• 한국전자거래학회지
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• 제19권3호
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• pp.107-123
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• 2014

텍스트마이닝 연구의 기본적인 난제는 기존 텍스트 표현모델이 자연어 문장으로 기술된 텍스트 데이터로부터 의미 또는 개념 정보를 표현하지 않는데 기인한다. 기존 텍스트 표현모델인 벡터공간 모델(vector space model), 불리언 모델(Boolean model), 통계 모델(statistical model), 텐서공간 모델(tensor space model) 등은 'Bag-of-Words' 방식에 바탕을 두고 있다. 이러한 텍스트 모델들은 텍스트에 포함된 단어와 그것의 출현 횟수만으로 텍스트를 표현하므로, 단어의 함축 의미, 단어의 순서 및 텍스트의 구조를 전혀 표현하지 못한다. 대부분의 텍스트 마이닝 기술은 대상 문서를 'Bag-of-Words' 방식의 텍스트 모델로 표현함을 전제로 하여 발전하여 왔다. 하지만 오늘날 빅데이터 시대를 맞이하여 방대한 규모의 텍스트 데이터를 보다 정밀하게 분석할 수 있는 새로운 패러다임의 표현모델을 요구하고 있다. 본 논문에서 제안하는 텍스트 표현모델은 개념공간을 문서 및 단어와 동등한 매핑 공간으로 상정하여, 그 세 가지 공간에 대한 연관 관계를 모두 표현한다. 개념공간의 구성을 위해서 위키피디어 데이터를 활용하며, 하나의 개념은 하나의 위키피디어 페이지로부터 정의된다. 결과적으로 주어진 텍스트 문서집합을 의미적으로 해석이 가능한 3차 텐서(3-order tensor)로 표현하게 되며, 따라서 제안 모델을 텍스트 큐보이드 모델이라 명명한다. 20Newsgroup 문서집합을 사용하여 문서 및 개념 수준의 클러스터링 정확도를 평가함으로써, 제안 모델이 'Bag-of-Word' 방식의 대표적 모델인 벡터공간 모델에 비해 우수함을 보인다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1086-1087
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• 2007

This paper presents a implementation of speed sensorless vector control algorithm of induction motor using MATLAB/SIMULINK. The proposed method utilize the combination of the voltage model based on stator equivalent model and the current model based on rotor equivalent model, which enables stable estimation of rotor flux. Estimated rotor speed, which is used to speed controller of induction motor, is based on estimated flux. The overall system consisted of speed controller with the most general PI controller, current controller, flux controller. Speed sensorless vector control algorithm is implemeted as block diagrams using MATLAB/SIMULINK. Realtime control is perform by dSPACE DS1104 control board and Real-Time-Interface(RTI).

• International Journal of Contents
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• 제1권2호
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• pp.26-30
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• 2005

According to the fast growth of information on the Internet, it is becoming increasingly difficult to find and organize useful information. To reduce information overload, it needs to exploit automatic text classification for handling enormous documents. Support Vector Machine (SVM) is a model that is calculated as a weighted sum of kernel function outputs. This paper describes a document classifier for web documents in the fields of Information Technology and uses SVM to learn a model, which is constructed from the training sets and its representative terms. The basic idea is to exploit the representative terms meaning distribution in coherent thematic texts of each category by simple statistics methods. Vector-space model is applied to represent documents in the categories by using feature selection scheme based on TFiDF. We apply a category factor which represents effects in category of any term to the feature selection. Experiments show the results of categorization and the correlation of vector length.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.163-165
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• 2006

This paper presents a implementation of speed sensorless vector control algorithm of induction motor using MATLAB/SIMULINK amd dSPACE DSl104 R&D board. The estimation of rotor flux linkage and rotor speed is carried out using model reference adaptive system(MRAS) method. Estimated rotor speed is used to speed controller of induction motor. Simulation results are presented to confirm speed sensorless vector control algorithm.