• Title/Summary/Keyword: use for learning

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Semi-supervised SAR Image Classification with Threshold Learning Module (임계값 학습 모듈을 적용한 준지도 SAR 이미지 분류)

  • Jae-Jun Do;Sunok Kim
    • The Journal of Bigdata
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    • v.8 no.2
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    • pp.177-187
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    • 2023
  • Semi-supervised learning (SSL) is an effective approach to training models using a small amount of labeled data and a larger amount of unlabeled data. However, many papers in the field use a fixed threshold when applying pseudo-labels without considering the feature-wise differences among images of different classes. In this paper, we propose a SSL method for synthetic aperture radar (SAR) image classification that applies different thresholds for each class instead of using a single fixed threshold for all classes. We propose a threshold learning module into the model, considering the differences in feature distributions among classes, to dynamically learn thresholds for each class. We compare the application of a SSL SAR image classification method using different thresholds and examined the advantages of employing class-specific thresholds.

Object Tracking Based on Exactly Reweighted Online Total-Error-Rate Minimization (정확히 재가중되는 온라인 전체 에러율 최소화 기반의 객체 추적)

  • JANG, Se-In;PARK, Choong-Shik
    • Journal of Intelligence and Information Systems
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    • v.25 no.4
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    • pp.53-65
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    • 2019
  • Object tracking is one of important steps to achieve video-based surveillance systems. Object tracking is considered as an essential task similar to object detection and recognition. In order to perform object tracking, various machine learning methods (e.g., least-squares, perceptron and support vector machine) can be applied for different designs of tracking systems. In general, generative methods (e.g., principal component analysis) were utilized due to its simplicity and effectiveness. However, the generative methods were only focused on modeling the target object. Due to this limitation, discriminative methods (e.g., binary classification) were adopted to distinguish the target object and the background. Among the machine learning methods for binary classification, total error rate minimization can be used as one of successful machine learning methods for binary classification. The total error rate minimization can achieve a global minimum due to a quadratic approximation to a step function while other methods (e.g., support vector machine) seek local minima using nonlinear functions (e.g., hinge loss function). Due to this quadratic approximation, the total error rate minimization could obtain appropriate properties in solving optimization problems for binary classification. However, this total error rate minimization was based on a batch mode setting. The batch mode setting can be limited to several applications under offline learning. Due to limited computing resources, offline learning could not handle large scale data sets. Compared to offline learning, online learning can update its solution without storing all training samples in learning process. Due to increment of large scale data sets, online learning becomes one of essential properties for various applications. Since object tracking needs to handle data samples in real time, online learning based total error rate minimization methods are necessary to efficiently address object tracking problems. Due to the need of the online learning, an online learning based total error rate minimization method was developed. However, an approximately reweighted technique was developed. Although the approximation technique is utilized, this online version of the total error rate minimization could achieve good performances in biometric applications. However, this method is assumed that the total error rate minimization can be asymptotically achieved when only the number of training samples is infinite. Although there is the assumption to achieve the total error rate minimization, the approximation issue can continuously accumulate learning errors according to increment of training samples. Due to this reason, the approximated online learning solution can then lead a wrong solution. The wrong solution can make significant errors when it is applied to surveillance systems. In this paper, we propose an exactly reweighted technique to recursively update the solution of the total error rate minimization in online learning manner. Compared to the approximately reweighted online total error rate minimization, an exactly reweighted online total error rate minimization is achieved. The proposed exact online learning method based on the total error rate minimization is then applied to object tracking problems. In our object tracking system, particle filtering is adopted. In particle filtering, our observation model is consisted of both generative and discriminative methods to leverage the advantages between generative and discriminative properties. In our experiments, our proposed object tracking system achieves promising performances on 8 public video sequences over competing object tracking systems. The paired t-test is also reported to evaluate its quality of the results. Our proposed online learning method can be extended under the deep learning architecture which can cover the shallow and deep networks. Moreover, online learning methods, that need the exact reweighting process, can use our proposed reweighting technique. In addition to object tracking, the proposed online learning method can be easily applied to object detection and recognition. Therefore, our proposed methods can contribute to online learning community and object tracking, detection and recognition communities.

A study on an identification procedure for control of nonlinear plants using neural networks

  • Lee, In-Soo;Jeon, Gi-Joon
    • 제어로봇시스템학회:학술대회논문집
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    • 1993.10b
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    • pp.127-131
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    • 1993
  • A new learning method of both NNI and NNC by which the NNI identifies precisely the dynamic characteristics of the plant is proposed. For control of ihe nonlinear plant we use two neural networks, one -for identification and the other for control. We define a closed loop en-or which depends on identification and control error. In the proposed learning method, the closed loop en-or is utilized to train the NNI and the NNC. Computer simulation results reveal that the NNC based on proposed method is insensitive to variations of the plant parameters.

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PID Learning Controller for Multivariable System with Dynamic Friction (동적 마찰이 있는 다변수 시스템에서의 PID 학습 제어)

  • Chung, Byeong-Mook
    • Journal of the Korean Society for Precision Engineering
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    • v.24 no.12
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    • pp.57-64
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    • 2007
  • There have been many researches for optimal controllers in multivariable systems, and they generally use accurate linear models of the plant dynamics. Real systems, however, contain nonlinearities and high-order dynamics that may be difficult to model using conventional techniques. Therefore, it is necessary a PID gain tuning method without explicit modeling for the multivariable plant dynamics. The PID tuning method utilizes the sign of Jacobian and gradient descent techniques to iteratively reduce the error-related objective function. This paper, especially, focuses on the role of I-controller when there is a steady state error. However, it is not easy to tune I-gain unlike P- and D-gain because I-controller is mainly operated in the steady state. Simulations for an overhead crane system with dynamic friction show that the proposed PID-LC algorithm improves controller performance, even in the steady state error.

Spatial Information Based Simulator for User Experience's Optimization

  • Bang, Green;Ko, Ilju
    • Journal of the Korea Society of Computer and Information
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    • v.21 no.3
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    • pp.97-104
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    • 2016
  • In this paper, we propose spatial information based simulator for user experience optimization and minimize real space complexity. We focus on developing simulator how to design virtual space model and to implement virtual character using real space data. Especially, we use expanded events-driven inference model for SVM based on machine learning. Our simulator is capable of feature selection by k-fold cross validation method for optimization of data learning. This strategy efficiently throughput of executing inference of user behavior feature by virtual space model. Thus, we aim to develop the user experience optimization system for people to facilitate mapping as the first step toward to daily life data inference. Methodologically, we focus on user behavior and space modeling for implement virtual space.

High Speed Tool Feed System by the Mechanism of Ball Screw and Servo Motor (볼 나사와 서보모터 메커니즘에 의한 고속 TOOL 이송장치)

  • 김성식;김경석
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.11
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    • pp.76-82
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    • 1998
  • In this study, the Ball screw and Servo motor Mechanism is considered as a High Speed Tool Feed System for the machining of a piston of a reciprocating engine. For the machining of a piston, that shapes oval, high speed servo mechanism is needed as a positioning of a cutting tool, and the stroke of tool is 0.1 mm ~ 1 mm. Ball screw and servo motor Mechanism is available very much because this mechanism is used widely in general machine. This Mechanism has been designed with the use of the decrease in mass and partial wear of the ball screw for high speed positioning of tool. Also the periodic learning control method with the inverse transfer function compensation has been applied to the positioning control for the high accuracy positioning of tool. These applications lead the achievement of the machining of a piston with an accuracy of 5${\mu}{\textrm}{m}$ at 2500 rpm in CNC turning.

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MOBILE LEARNING SYSTEM FOR NUMERICAL ANALYSIS BY USING PHP

  • KIM, SANG-BAE
    • Journal of applied mathematics & informatics
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    • v.37 no.1_2
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    • pp.157-162
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    • 2019
  • Programming tools are essential for students learning numerical analysis. It is troublesome to go to a laboratory where a computer is located after taking a lecture. Nowadays most students have mobile phones which can be used for programming practice through the Internet. PHP is a server-side scripting language designed for web development but also used as a general-purpose programming language. However, PHP has many inconveniences, such as adding a dollar symbol ($) to every varable. This paper introduces a slightly modified language, NAPHP, and a system which is designed for students to use their own mobile phone to write down the language NAPHP and run it on the web page. The system NAPHP-SYS is an educational tool that turns NAPHP into PHP, run PHP code and show the results on the web.

Labeling Big Spatial Data: A Case Study of New York Taxi Limousine Dataset

  • AlBatati, Fawaz;Alarabi, Louai
    • International Journal of Computer Science & Network Security
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    • v.21 no.6
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    • pp.207-212
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    • 2021
  • Clustering Unlabeled Spatial-datasets to convert them to Labeled Spatial-datasets is a challenging task specially for geographical information systems. In this research study we investigated the NYC Taxi Limousine Commission dataset and discover that all of the spatial-temporal trajectory are unlabeled Spatial-datasets, which is in this case it is not suitable for any data mining tasks, such as classification and regression. Therefore, it is necessary to convert unlabeled Spatial-datasets into labeled Spatial-datasets. In this research study we are going to use the Clustering Technique to do this task for all the Trajectory datasets. A key difficulty for applying machine learning classification algorithms for many applications is that they require a lot of labeled datasets. Labeling a Big-data in many cases is a costly process. In this paper, we show the effectiveness of utilizing a Clustering Technique for labeling spatial data that leads to a high-accuracy classifier.

An Analysis on the Factors of Information Literacy Ability for Young Children (유아의 정보능력에 영향을 미치는 요인탐색)

  • Kwon, Jung-Sim;Kang, Sang;Shin, Ji-Hae
    • Korean Journal of Childcare and Education
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    • v.6 no.2
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    • pp.1-15
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    • 2010
  • The purpose of this study is to investigate the difference between using computers for an Information Literacy Abilities of Young Children(ILAYC) and development of the ILAYC, with regard to following factors: computer use at home, learning in educational facilities for early childhood, and parents' recognition toward computer-assisted education. The data were obtained from random sampling of 4-year old children in educational facilities for early childhood located in J city. The research was conducted in order to measure ILAYC, using the questionnaire for teachers from September 3 to 27, 2009. The t-test to investigate computer utilization ability and information literacy ability for young children revealed that the ILAYC was not significantly influenced by their computer use at home, while the ILAYC varied with learning in educational facilities and parents' recognition toward computer-assisted education. These are resulted from parents' different recognition toward computer-assisted education when they select an educational facility for early childhood.

The Use of Technology with a Calculator for Improving Mathematical Thinking in Learning and Teaching Mathematics - A Study of Students' Mathematization Using Technology - (수학 교수.학습과정에서 사고력 신장을 위한 계산기의 활용 - 학생들의 수학화 발달에서 테크놀로지의 효과 -)

  • Choi-Koh, Sang-Sook;Ko, Ho-Kyoung
    • The Mathematical Education
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    • v.46 no.1 s.116
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    • pp.97-122
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    • 2007
  • This article provides how to implement the use of Realistic Mathematics Education (RME) in a teaching a function at a school to improve students' mathematization for their mathematical thinking using technology, This study was planed to get research results using the mixed methodology with quantitative and qualitative methodologies. 120 middle school students participated in the study to bring us data about their mathematical achievement and disposition. Through the data analysis used ANCOVA, the students with the experiment of the mathematization and technology excelled the other groups of students who were not provided with technology or both of them. In analysis of the questions of the achievement test, the problems for vertical mathematization were presented harder for the students than the other problems for horizontal and applicative mathematization. The technology environment might have helped students manipulate the application of real-life problems easier. This means that teachers can put more careful assignment on vertical mathematization using technology. We also explored that learning and teaching under RME using technology encouraged students to refine and develop their informal functional concept and pursue higher thinking of formalization. The study results in a lot of resources for teachers to use into their teaching mathematics for improving students' mathematical thinking.

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