• Title/Summary/Keyword: Transformation Space Model

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Label Embedding for Improving Classification Accuracy UsingAutoEncoderwithSkip-Connections (다중 레이블 분류의 정확도 향상을 위한 스킵 연결 오토인코더 기반 레이블 임베딩 방법론)

  • Kim, Museong;Kim, Namgyu
    • Journal of Intelligence and Information Systems
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    • v.27 no.3
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    • pp.175-197
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    • 2021
  • Recently, with the development of deep learning technology, research on unstructured data analysis is being actively conducted, and it is showing remarkable results in various fields such as classification, summary, and generation. Among various text analysis fields, text classification is the most widely used technology in academia and industry. Text classification includes binary class classification with one label among two classes, multi-class classification with one label among several classes, and multi-label classification with multiple labels among several classes. In particular, multi-label classification requires a different training method from binary class classification and multi-class classification because of the characteristic of having multiple labels. In addition, since the number of labels to be predicted increases as the number of labels and classes increases, there is a limitation in that performance improvement is difficult due to an increase in prediction difficulty. To overcome these limitations, (i) compressing the initially given high-dimensional label space into a low-dimensional latent label space, (ii) after performing training to predict the compressed label, (iii) restoring the predicted label to the high-dimensional original label space, research on label embedding is being actively conducted. Typical label embedding techniques include Principal Label Space Transformation (PLST), Multi-Label Classification via Boolean Matrix Decomposition (MLC-BMaD), and Bayesian Multi-Label Compressed Sensing (BML-CS). However, since these techniques consider only the linear relationship between labels or compress the labels by random transformation, it is difficult to understand the non-linear relationship between labels, so there is a limitation in that it is not possible to create a latent label space sufficiently containing the information of the original label. Recently, there have been increasing attempts to improve performance by applying deep learning technology to label embedding. Label embedding using an autoencoder, a deep learning model that is effective for data compression and restoration, is representative. However, the traditional autoencoder-based label embedding has a limitation in that a large amount of information loss occurs when compressing a high-dimensional label space having a myriad of classes into a low-dimensional latent label space. This can be found in the gradient loss problem that occurs in the backpropagation process of learning. To solve this problem, skip connection was devised, and by adding the input of the layer to the output to prevent gradient loss during backpropagation, efficient learning is possible even when the layer is deep. Skip connection is mainly used for image feature extraction in convolutional neural networks, but studies using skip connection in autoencoder or label embedding process are still lacking. Therefore, in this study, we propose an autoencoder-based label embedding methodology in which skip connections are added to each of the encoder and decoder to form a low-dimensional latent label space that reflects the information of the high-dimensional label space well. In addition, the proposed methodology was applied to actual paper keywords to derive the high-dimensional keyword label space and the low-dimensional latent label space. Using this, we conducted an experiment to predict the compressed keyword vector existing in the latent label space from the paper abstract and to evaluate the multi-label classification by restoring the predicted keyword vector back to the original label space. As a result, the accuracy, precision, recall, and F1 score used as performance indicators showed far superior performance in multi-label classification based on the proposed methodology compared to traditional multi-label classification methods. This can be seen that the low-dimensional latent label space derived through the proposed methodology well reflected the information of the high-dimensional label space, which ultimately led to the improvement of the performance of the multi-label classification itself. In addition, the utility of the proposed methodology was identified by comparing the performance of the proposed methodology according to the domain characteristics and the number of dimensions of the latent label space.

Investigation into SINS/ANS Integrated Navigation System Based on Unscented Kalman Filtering

  • Ali, Jamshaid;Jiancheng, Fang
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.241-245
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    • 2005
  • Strapdown inertial navigation system (SINS) integrated with astronavigation system (ANS) yields reliable mission capability and enhanced navigational accuracy for spacecrafts. The theory and characteristics of integrated system based on unscented Kalman filtering is investigated in this paper. This Kalman filter structure uses unscented transform to approximate the result of applying a specified nonlinear transformation to a given mean and covariance estimate. The filter implementation subsumed here is in a direct feedback mode. Axes misalignment angles of the SINS are observation to the filter. A simple approach for simulation of axes misalignment using stars observation is presented. The SINS error model required for the filtering algorithm is derived in space-stabilized mechanization. Simulation results of the integrated navigation system using a medium accuracy SINS demonstrates the validity of this method on improving the navigation system accuracy with the estimation and compensation for gyros drift, and the position and velocity errors that occur due to the axes misalignments.

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Uncertainty Modeling and Robust Control for LCL Resonant Inductive Power Transfer System

  • Dai, Xin;Zou, Yang;Sun, Yue
    • Journal of Power Electronics
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    • v.13 no.5
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    • pp.814-828
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    • 2013
  • The LCL resonant inductive power transfer (IPT) system is increasingly used because of its harmonic filtering capabilities, high efficiency at light load, and unity power factor feature. However, the modeling and controller design of this system become extremely difficult because of parameter uncertainty, high-order property, and switching nonlinear property. This paper proposes a frequency and load uncertainty modeling method for the LCL resonant IPT system. By using the linear fractional transformation method, we detach the uncertain part from the system model. A robust control structure with weighting functions is introduced, and a control method using structured singular values is used to enhance the system performance of perturbation rejection and reference tracking. Analysis of the controller performance is provided. The simulation and experimental results verify the robust control method and analysis results. The control method not only guarantees system stability but also improves performance under perturbation.

Content-Based Image Retrieval System using Feature Extraction of Image Objects (영상 객체의 특징 추출을 이용한 내용 기반 영상 검색 시스템)

  • Jung Seh-Hwan;Seo Kwang-Kyu
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.27 no.3
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    • pp.59-65
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    • 2004
  • This paper explores an image segmentation and representation method using Vector Quantization(VQ) on color and texture for content-based image retrieval system. The basic idea is a transformation from the raw pixel data to a small set of image regions which are coherent in color and texture space. These schemes are used for object-based image retrieval. Features for image retrieval are three color features from HSV color model and five texture features from Gray-level co-occurrence matrices. Once the feature extraction scheme is performed in the image, 8-dimensional feature vectors represent each pixel in the image. VQ algorithm is used to cluster each pixel data into groups. A representative feature table based on the dominant groups is obtained and used to retrieve similar images according to object within the image. The proposed method can retrieve similar images even in the case that the objects are translated, scaled, and rotated.

Delay-Dependent Guaranteed Cost Control for Uncertain Neutral Systems with Distributed Delays

  • Li, Yongmin;Xu, Shengyuan;Zhang, Baoyong;Chu, Yuming
    • International Journal of Control, Automation, and Systems
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    • v.6 no.1
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    • pp.15-23
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    • 2008
  • This paper considers the problem of delay-dependent guaranteed cost controller design for uncertain neutral systems with distributed delays. The system under consideration is subject to norm-bounded time-varying parametric uncertainty appearing in all the matrices of the state-space model. By constructing appropriate Lyapunov functionals and using matrix inequality techniques, a state feedback controller is designed such that the resulting closed-loop system is not only robustly stable but also guarantees an adequate level of performance for all admissible uncertainties. Furthermore, a convex optimization problem is introduced to minimize a specified cost bound. By matrix transformation techniques, the corresponding optimal guaranteed controller can be obtained by solving a linear matrix inequality. Finally, a simulation example is presented to demonstrate the effectiveness of the proposed approach.

ON THE STUDY OF SOLUTION UNIQUENESS TO THE TASK OF DETERMINING UNKNOWN PARAMETERS OF MATHEMATICAL MODELS

  • Avdeenko, T.V.;Je, Hai-Gon
    • East Asian mathematical journal
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    • v.16 no.2
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    • pp.251-266
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    • 2000
  • The problem of solution uniqueness to the task of determining unknown parameters of mathematical models from input-output observations is studied. This problem is known as structural identifiability problem. We offer a new approach for testing structural identifiability of linear state space models. The approach compares favorably with numerous methods proposed by other authors for two main reasons. First, it is formulated in obvious mathematical form. Secondly, the method does not involve unfeasible symbolic computations and thus allows to test identifiability of large-scale models. In case of non-identifiability, when there is a set of solutions to the task, we offer a method of computing functions of the unknown parameters which can be determined uniquely from input-output observations and later used as new parameters of the model. Such functions are called parametric functions capable of estimation. To develop the method of computation of these functions we use Lie group transformation theory. Illustrative example is given to demonstrate applicability of presented methods.

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Representation of Uncertain Geometric Robot Environment Using Fuzzy Numbers

  • Kim, Wan-Joo-;Ko, Joong-Hyup;Chung, Myung-Jin
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 1993.06a
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    • pp.1211-1214
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    • 1993
  • In this paper, we present a fuzzy-number-oriented methodology to model uncertain geometric robot environment and to manipulate geometric uncertainty between robot coordinate frames. We describe any geometric primitive of robot environment as a parameter vector in parameter space. Not only ill-known values of the parameterized geometric primitive but the uncertain quantities of coordinate transformation are represented by means of fuzzy numbers restricted to appropriate membership functions. For consistent interpretation about geometric primitives between different coordinate frames, we manipulate these uncertain quantities using fuzzy arithmetic.

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A Speed Control of A Series DC Motor Using Adaptive Fuzzy Sliding-Mode Method (적응 퍼지 슬라이딩 모드 기법을 이용한 Series DC 모터의 속도제어)

  • Kim, Do-Woo;Yang, Hai-Won;Jung, Gi-Chul;Lee, Hyo-Sup
    • Proceedings of the KIEE Conference
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    • 2001.07d
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    • pp.2292-2295
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    • 2001
  • In this paper, The control problem for a series DC motor is considered to adaptive fuzzy sliding-mode control scheme. Based on a nonlinear mathematical model of a series connected DC motor, instead of the combination of a nonlinear transformation and state feedback(feedback linearization) reduces the nonlinear control design. To demonstrate its effectiveness, an experimental study of this controller is presented. Two sets of fuzzy rule bases are utilized to represent the equivalent control input with unknown system functions of the main target. The membership functions of the THEN-part, which is used to construct a suitable equivalent control of SMC, are changed according to the adaptive law. With such a design scheme, we not only maintain the distribution of membership functions over state space but also reduce computing time considerably.

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Impediments to Driving Smart Cities: a Case Study of South Korea

  • Kim, Yiinjung;Hwang, Ha;Choi, Hojin
    • Asian Journal of Innovation and Policy
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    • v.10 no.2
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    • pp.159-176
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    • 2021
  • Over the past two decades, smart cities have been attracting attention as a means of solving urban problems and as a model for securing urban sustainability. Many studies have been conducted in various fields such as conceptual definitions, classification, new technologies, case analysis, and civic participation of smart cities. In particular, applicable technologies and their importance have been highlighted so far. However, since a city is a complex and meta-systematic space, it is the overly optimistic prospect that technology, one of the smart city components, will lead to successful smart cities. This study elucidates the impediments to driving smart cities as a case study of South Korea, a leading country in smart technology and digital transformation. We examined three comprehensive national plans for promoting smart cities and conducted focus group interviews with experts in smart cities to analyze the obstacles to carrying smart cities. We classified the thirteen impediments into technological, industrial, governmental, and social factors as a result. Some of them are generic issues in policy establishment and enforcement, while others are specific to smart cities.

Search Space Reduction Model for Keyword Query Transformation on Semantic Search (시맨틱 검색에서 키워드 질의 변환을 위한 탐색 공간 축소 모델)

  • Yeom, Jeong-Nam;Cho, Joon-Myun;Yoo, Jeong-Ju
    • Annual Conference of KIPS
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    • 2013.11a
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    • pp.1390-1393
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    • 2013
  • 인터페이스가 제한된 단말에서 정보 검색 서비스를 제공하는 경우, 검색 재현율보다는 정확도가 중요하다. 데이터를 쉽게 구조화할 수 있고 검색 정확도가 중요한 한정된 도메인에서는 시맨틱 검색 기술을 통해 강력한 정보 검색 서비스를 제공할 수 있지만, 사용자 키워드 질의를 시스템 질의로 변환하는 과정에서 다양한 해석들이 존재할 수 있기에 개선의 여지도 많다. 본 논문에서는 해석 정확도와 확장성을 동시에 향상시키기 위한 새로운 모델을 제안한다. 제안 모델은 공간의 구조와 요소들의 해석을 제한함으로써 중간 탐색 공간의 크기를 점진적으로 줄이면서 사용자의 검색 의도는 가능한 보존할 수 있다. 실제 데이터로 이루어진 대용량 지식을 이용해 다른 최신 기술과 비교하여 실험적 평가를 제시하였다.