• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.230-235
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• 1992

We propose a method of generating data to train a neural network controller. The data can be prepared directly by an iterative learning technique which repeatedly adjusts the control input to improve the tracking quality of the desired trajectory. Instead of storing control input data in memory as in iterative learning control, the neural network stores the mapping between the control input and the desired output. We apply this concept to the trajectory control of a two link robot manipulator with a feedforward neural network controller and a feedback linear controller. Simulation results show good generalization of the neural network controller.

• Korean Security Journal
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• no.13
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• pp.91-112
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• 2007

The purpose of this study is to identify effect of superior leadership style in private security service on job satisfaction. The survey research tool was a questionnaire. The subjects of this study were selected from the population of private security service employee's and sampled by using convenience sampling. Data obtained from 448 athletes were used. Questionnaire was used as a tool to attain the purpose of this study, SPSS 12.0 program was used to analyze the data, and statistical tests including correlation analysis and multiple regression analysis were conducted at significance level of p<.05. The results of this study were as follows. First, the democratic behavior, affirmative feedback, training and direction and social support in leadership style have a significant effect on a satisfaction of relation with supervisor. Second, the democratic behavior, affirmative feedback and training and direction in leadership style have a significant effect on a satisfaction of relation with coworkers. Third, the democratic behavior, affirmative feedback and training and direction in leadership style have a significant effect on a satisfaction of work. Fourth, the democratic behavior and authoritative behavior in leadership style have a significant effect on a satisfaction of pay. Finally, the democratic behavior, affirmative feedback and training and direction in leadership style have a significant effect on a satisfaction of promotion opportunity.

• Journal of KIISE:Databases
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• v.36 no.6
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• pp.434-445
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• 2009

Content-based image retrieval(CBIR) is the retrieval technique which uses the contents of images. However, in contrast to text data, multimedia data are ambiguous and there is a big difference between system's low-level representation and human's high-level concept. So it doesn't always mean that near points in the vector space are similar to user. We call this the semantic-gap problem. Due to this problem, performance of image retrieval is not good. To solve this problem, the relevance feedback(RF) which uses user's feedback information is used. But existing RF doesn't consider user's region-of-interest(ROI), and therefore, irrelevant regions are used in computing new query points. Because the system doesn't know user's ROI, RF is proceeded in the image-level. We propose a new ROI RF method which guides a user to select ROI from relevant images for the retrieval of complex satellite image, and this improves the accuracy of the image retrieval by computing more accurate query points in this paper. Also we propose a pruning technique which improves the accuracy of the image retrieval by using images not selected by the user in this paper. Experiments show the efficiency of the proposed ROI RF and the pruning technique.

• Journal of The Korean Association For Science Education
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• v.42 no.5
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• pp.501-514
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• 2022

This study aims to reveal what is necessary for pre-service science teachers to make good use of online formative assessment in the context of online classes. For 22 pre-service physics teachers, first, the preliminary perception of online classes, online formative assessment, and formative assessment was investigated; second, the practice process of online formative assessment was examined. Then the differences between perception and practice were compared and analyzed. Data were collected in preliminary surveys, lesson plans, online formative assessment items, and interview data. As a result of the study, an interaction was mentioned as the difficulty of online classes in the preliminary perception, and pre-service teachers mentioned the use of technology, feedback, and adjustment as advantages of online formative assessment. In most cases of practice, the automated feedback was used using the platform's technology, but it did not lead to adjustment and interaction. In addition, the use of items in online formative assessment was not suitable for formative functions. The reason why the interaction using formative feedback did not occur seems to be because the understanding of formative assessment was insufficient. Pre-service teachers need to be prepared for the 'formative' function through the feedback of online formative assessment so that can lead to interaction in online classes. The shift to online classes is creating difficulties, especially in interaction. It is necessary to prepare and educate pre-service teachers on fundamental aspects that can overcome these difficulties.

• Journal of the Korean Society of School Health
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• v.30 no.2
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• pp.103-112
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• 2017

Purpose: The Purpose of this study was to examine school health teachers' burnout, engagement, job demands and job resources and to identify the factors that influence burnout and engagement. Methods: The participants were 222 school health teachers working in elementary, middle or high schools. Data were analyzed using descriptive statistics, t-test, ANOVA, Pearson's correlation coefficient, and hierarchical multiple regression. Results: The significant factors influencing burnout were rewards (${\beta}=-.51$), autonomy (${\beta}=-.15$), and job demands (${\beta}=.13$). These factors explained 42% of the variance in burnout. The significant factors influencing engagement were feedback (${\beta}=.49$), rewards (${\beta}=.21$), type of employment (${\beta}=.15$) and autonomy (${\beta}=.13$). These factors explained 49% of the variance in engagement. Conclusion: The study showed that job demands increase burnout, while job resources such as rewards and autonomy alleviate it. In addition, job resources, such as feedback, rewards and autonomy, increase engagement among school health teachers. Therefore, in order to reduce burnout and increase engagement among school health teachers, it is necessary to reduce the level of job demands and to provide enough job resources such as rewards, autonomy and feedback by improving the job environment.

• ETRI Journal
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• v.36 no.1
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• pp.62-68
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• 2014

This paper presents a novel user selection method based on the signal-to-interference-plus-noise ratio (SINR), which is approximated using limited feedback data at the base stations (BSs) of multiple user multiple-input multiple-output (MU-MIMO) systems. In the proposed system, the codebook vector index, the quantization error obtained from the correlation between the measured channel and the codebook vector, and the measured value of the largest singular value are fed back from each user to the BS. The proposed method not only generates precoding vectors that are orthogonal to the precoding vectors of the previously selected users and are highly correlated with the codebook vector of each user but also adopts the quantization error in approximating the SINR, which eventually provides a significantly more accurate SINR than the conventional SINR-based user selection techniques. Computer simulations show that the proposed method enhances the sum rate of the conventional SINR-based methods by at least 2.4 (2.62) bps/Hz when the number of transmit antennas and number of receive antennas per user terminal is 4 and 1(2), respectively, with 100 candidate users and an SNR of 30 dB.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.8
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• pp.1489-1496
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• 2010

A feed forward differential architecture of analog PRML decoder is investigated to implement on analog parallel processing circuits. The conventional PRML decoder performs the trellis processing with the implementation of single stage in digital and its repeated use. The analog parallel processing-based PRML comes from the idea that the decoding of PRML is done mainly with the information of the first several number of stages. Shortening the trellis processing stages but implementing it with analog parallel circuits, several benefits including higher speed, no memory requirement and no A/D converter requirement are obtained. Most of the conventional analog parallel processing-based PRML decoders are differential architecture with the feedback of the previous decoded data. The architecture used in this paper is without feedback, where error metric accumulation is allowed to start from all the states of the decoding stage, which enables to be decoded without feedback. The circuit of the proposed architecture is simpler than that of the conventional analog parallel processing structure with the similar decoding performance. Characteristics of the feed forward differential architecture are investigated through various simulation studies.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.11
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• pp.1069-1076
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• 2007

This paper presents the road simulator control technology for reproducing the road input signal to implement the real road data. The simulator consists of the hydraulic pump, servo valve, hydraulic actuator and its control equipment. The QFT(Quantitative Feedback Theory) is utilized to control the simulator effectively. The control system illustrates a tracking performance of the closed-loop controller with low order transfer function G(s) and pre-filter F(s) for a parametric uncertain model. A force controller is designed to communicate the control signal between simulator and digital controller. Tracking specification is satisfied with upper and lower bound tolerances on the steep response of the system to the reference signal. The efficacy of the QFT force controller is verified through the numerical simulation, in which combined dynamics and actuation of the hydraulic servo system are tested. The simulation results show that the proposed control technique works well under uncertain hydraulic plant system. The conventional software (Labview) is used to make up for the real controller in the real-time basis, and the experimental works show that the proposed algorithm works well for a single road simulator.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1132-1136
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• 2005

In this paper, adaptive equalizer receiver for a turbo code direct sequence code division multiple access (DSCDMA) by using least mean square (LMS) adaptive algorithm is presented. The proposed adaptive equalizer is using soft output of decision feedback adaptive equalizer (DFE) to examines the output of the equalizer and the Log- maximum a posteriori (Log-MAP) algorithm for the turbo decoding process of the system. The objective of the proposed equalizer is to minimize the bit error rate (BER) of the data due to the disturbances of noise and intersymbol interference (ISI)phenomenon on the channel of the DS-CDMA digital communication system. The computer program simulation results shown that the proposed soft output decision feedback adaptive equalizer provides a good BER than the others one such as conventional adaptive equalizer, infinite impulse response adaptive equalizer.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.1
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• pp.12-17
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• 2014

In this paper, we propose a controller capable of reducing the effect of measurement errors under AC and DC noise. Typically, the control system measures data through a sensor. If sensor noise is included in a controller via the feedback channel, the signal is distorted and the entire system cannot work normally. Therefore, some appropriate action to counter the measurement error effect is essential in the controller design. Our controller is equipped with a gain-scaling factor and a compensator to reduce the effect of measurement error in the feedback signal. Also, we use a switching control strategy to enhance the performance of the controller regarding convergence speed. Our proposed controller can therefore effectively reduce the AC and DC noise of the sensor. We analyze the proposed controller by Laplace transform technique and our control method is verified via MATLAB simulation.