• Journal of Power System Engineering
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• v.11 no.3
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• pp.66-72
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• 2007

This study proposed new method to decide the reference model necessary for design PID controller. In generally, control design problems using the reference model have the following two factors. One factor is that numerical model of the controlled system can be obtained extremely, and the other is that specification for the closed-loop dynamic performance is pure moderate. Therefore, the control design procedure is essentially based on the partial reference model matching which offers a reasonable method to simplify the design and the controller configuration under the controlled system uncertainty. ITAE(Integral of time-multiplied absolute error) performance index and Kitamori method etc. which were used a reference model method had a limit to settling time and rising time of reference model that it arrived to steady state response according to the controlled system. On this study, if it only knew peak time of overshoot and settling time by measurement signal of the controlled system, it can be made the reference model easily. We proposed new method to improve performance index of the reference model superior to existing reference model index and illustrate the numerical simulation results to show the effectiveness of proposed control method design.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.8
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• pp.1511-1513
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• 2007

A new reference point location method using the cosine component is proposed, where an edge map is defined and used to find the reference point. Because all processes used in the proposed method are performed at the block level, less processing time is required. Experimental results show that the proposed method can effectively detect the reference point with higher speed and accuracy for all types of fingerprints.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.6
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• pp.890-897
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• 2003

This paper compares engineering estimation schemes of C＊ and creep COD for circumferential and axial through-wall cracked pipes at elevated temperatures with detailed 3-D elastic-creep finite element results. Engineering estimation schemes included the GE/EPRI method, the reference stress method where reference stress is defined based on the plastic limit load and the enhanced reference stress method where the reference stress is defined based on the optimized reference load. Systematic investigations are made not only on the effect of creep-deformation behaviour on C＊ and creep COD, but also on effects of the crack location, the pipe geometry, the crack length and the loading mode. Comparison of the FE results with engineering estimations provides that for idealized power law creep, estimated C＊ and COD rate results from the GE/EPRI method agree best with FE results. For general creep-deformation laws where either primary or tertiary creep is important and thus the GE/EPRI method is hard to apply, on the other hand, the enhanced reference stress method provides more accurate and robust estimations for C* and COD rate than the reference stress method.

• The Research Journal of the Costume Culture
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• v.5 no.1
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• pp.151-164
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• 1997

This study pursues the problems of plan photogrammetry which is widely used in somatotyping at present, and find out a method which can improve accuracy of measurement on the basis of principles and mechanisms of photography-the basic foundation of the photographic analysis methods. As a result, this study proposes a new method which is based on the reference point method and perspective coordinate system. And the test measurement was operated to compare the measurement accuracy of the proposed method and the method based on reference grid screen method and perpendicular coordinate system which is commonly used at present. The result of this test measurement showed that the proposed method has higher accuracy. Two reasons can be pointed out for the improvement of measuring accuracy. The first reason is that the proposed perspective coordinate system reduces the perspective distortion of photography. And second reason is that measuring points can be closely placed to the scale and coordinate reference plan of measurement by the proposed reference point method which make possible to place measuring object (or person) at the center of scale and coordinate reference plan by utilizing reference points of measurement in the three dimensional space not on screen.

• The Journal of the Acoustical Society of Korea
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• v.23 no.4
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• pp.282-287
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• 2004

This paper proposes the nearfield eigenvector method for array shape estimation using reference signals basted on the nearfield signal modeling. Generally. direction finding methods assume the reference signals to be plainwave. However, in case of the reference signals in nearfield, this assumption is inadequate for array shape estimation. In this paper. the nearfield reference signals are modeled. and we propose the nearfield eigenvector method. The numerical experiments indicated that the proposed method shows good performance for array shape estimation regardless of the ranges of the reference signals.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.705-708
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• 2003

In this paper, we have evaluated the methods to generate the reference signal for the diagnosis of multi-channel signals. The channel signal integrity can be known by the difference between the reference signal and each channel value. The generation method of reference signal is important in the diagnosis of multi-channel measurement system. The continuous weighting average method rejects the abnormal signal using weighting method and makes the reference signal using sumation of all channel values. This gives the simple and reasonable reference signal. The principle component analysis, one of the multivariate analysis methods, and the neural network method give the reliable reference signal by using signal models, and learning algorithm. Two methods can make the reliable reference if all signals are normal, but any signal having the drift have an effect on the reference.

• Journal of Positioning, Navigation, and Timing
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• v.8 no.3
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• pp.129-138
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• 2019

In this work, we propose detection method for ionosphere storm that occurs locally using widespread GNSS reference stations. For ionosphere storm detection, we compare ionosphere condition with other reference stations and estimate direction of movement based on ionosphere time variation. The method use carrier phase measurement of dual frequency, for accuracy and precision of test statistics, are evaluated with multiple GNSS reference stations data.

• Journal of Korean Library and Information Science Society
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• v.28
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• pp.93-135
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• 1998

The purpose of this study was to compare the effectiveness of programmed instruction versus lecture and discussion method on the knowledge of basic reference sources among undergraduate library and information science students. The hypotheses of the study were: 1. Programmed instruction will be more effective than the lecture/discussion method with regard to academic achievement. 2. There will be a significant difference in learning time between the experimental and the control groups. Seventy-eight library and information science students were participated m the study from the two universities in Chungchong Province. A programmed instruction manual, including 4-types of reference sources-dictionary, encyclopaedia, bibliography, indexes and abstracts, 40-item multiple choice post-test, and a questionnaire for the students' attitude toward programmed instruction were developed specifically for this research. The post-test only control-group design was selected for this experimental study. Students were given instruction on the specific reference titles in dictionary, encyclopedia, bibliography, indexes and abstracts. The control group was instructed by the lecture and discussion method while the experimental group completed a programmed instruction manual by themselves. Both the control and the experimental group were tested right after the instruction of 4-types of reference sources. In addition, a questionnaire asking students' attitude toward programmed instruction was administered to the experimental group. The findings from this study are summarized as follows: 1. The results showed that there were no significant difference in the mean of the post test score between the two groups. Therefore, programmed instruction is viable as an alternative method of instruction in the teaching of reference sources. 2. There was a significant difference in the mean of time spending for the leaning of bibliography, indexes and abstracts between the two groups. Accordingly, programmed instruction proved to be more efficient than the conventional lecture/discussion method in terms of learning time. 3. Students showed positive response to programmed instruction and evaluated it very interesting and challenging. In conclusion, the programmed instruction method was just as effective as the lecture/discussion method in the teaching of reference sources. And students' attitude toward the programmed instruction was favorable enough to secure a continued use of this method for the teaching of reference sources.

• The Journal of the Acoustical Society of Korea
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• v.23 no.2
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• pp.125-133
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• 2004

Most of the way shape estimation method using reference sources assume that the reference sources are in the farfield. That is, the reference sources are assumed to be far from the array. However, in applications of the array with reference sources, the reference sources are not far from the way, so that in practical ocean environments, the conventional method using farfield source model fail to estimate the positions of the hydrophones. In this paper, based on the nearfield source model, a subspace-based array shape estimation method was proposed. In the proposed method, nearfield reference source is modeled using the differential time delay at each hydrophone, and nearfield parameters are derived. Using these parameters, a subspace-based array shape estimation method that generalizes the existing farfield subspace fitting method which can work regardless of the range of the source is proposed. The Cramer-Rao lower bound for the proposed method is investigated. The results of the numerical experiments indicate that the proposed method performs well in estimating the shape of a perturbed way regardless of the ranges of the reference sources.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.1
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• pp.284-291
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• 1995

This paper proposes a method for determination of optimal reference spectrum in random vibration control. The least square method is used to minimize the spectrum deviation between the specified reference spectrum and spectra at the specimen-mounted points. This method needs only the measured FRF's at the control point and specimen-mounted points in pre-vibration test. Using the proposed method as reference spectrum, it is possible to easily predict spectra at the specimen-mounted points, and also to reduce overtest resulting from dynamic characteristics of shaker and fixture. This method is shown through theoretical and experimental results to be an effective method.