• Title/Summary/Keyword: Two-step Method

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Design and Performance Evaluation of Micro Stepping Actuator with a Variable Step Size (가변 스텝 마이크로 액츄에이터의 설계 및 구동특성)

  • Lim, Y.M.;Kim, S.H.;Kwak, Y.K.
    • Journal of the Korean Society for Precision Engineering
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    • v.12 no.7
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    • pp.26-31
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    • 1995
  • A new actuating mechanism suitable for a micro positioning device is developed using piezo-electric elements. The actuator can make a step movement of 0.5 .mu. m up to 3.5 .mu. m. The step size can be adjusted on demand. By repeating this step action, long distance movement is achieved. Precise positioning can be obtained by combining the coarse motion with the maximum step size and fine motion. Two types of fine motion have been proposed for a driving method. Firstly, feedback control bases on PID is applied. The experimental results for the two method are presented.

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A 4-step Inference Method for Natural Language Propositions Involving Fuzzy Quantifiers and Truth Qualifiers

  • Okamoto, Wataru
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2003.09a
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    • pp.579-582
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    • 2003
  • In this paper, we propose a 4-step inference method needed for constructing a natural language communication system. The method is used to obtain fuzzy quantifier Q′when QA is Fisr τ⇔ Q′(m′A) is mF is m"is τ is inferred (Q, Q′: quantifiers, A: fuzzy subject, m′, m": modifiers, y: fuzzy predicate, τ: truth qualifier). We show that Q′is resolved step by step for two types of Q, including a non-increasing type (few,...) and a non-decreasing type(most,...).

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Experimental Study of Two-step Phase-shifting Digital Holography based on the Calculated Intensity of a Reference Wave

  • Li, Jun;Pan, Yang Yang;Li, Jiao sheng;Li, Rong;Zheng, Tao
    • Journal of the Optical Society of Korea
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    • v.18 no.3
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    • pp.230-235
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    • 2014
  • Two-step quadrature phase-shifting digital holography based on the calculated intensity of a reference wave is proposed. In the Mach-Zehnder interferometer (MZI) architecture, the method only records two quadrature-phase holograms, without reference-wave intensity or object-wave intensity measurement, to perform object recoding and reconstruction. When the reference-wave intensity is calculated from the 2D correlation coefficient (CC) method that we presented, the clear reconstruction image can be obtained by some specific algorithm. Its feasibility and validity were verified by a series of experiments with 2D objects and 3D objects. The presented method will be widely used in real-time or dynamic digital holography applications.

Reduction of the Blocking Effect in Block Coded Images Using Human Visual Model (인간 시각 모델을 이용한 블록 부호화에서의 경계 현사의 제거)

  • 김근형;박래홍
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.25 no.6
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    • pp.663-671
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    • 1988
  • In this paper, in order to reduce the blocking effect of block coded images, we propose the method considering the lowpass and bandpass components of Granrath's human visual model. This method consists of two-stage enhancement procedure. The first step is lowpass filtering which smooths out the blocking effect, and the second step is a high frequency enhancement procedure to increase the contrast decreased by the lowpass filtering in the first step. In the first step, the one-dimensional Gaussian filter which aligthns parallel to the edge direction is considered to preserve the edge in the block and the two-dimensional Gaussian filter is used to smooth out the blocking effect near the block boundaries. In the second step, the lowpass and bandpass components of the Granrath's model are considered to increase contrast in a restored image. The performance comparison of the proposed method and the existing mehtods is made by a computer simulation with several block coded images. We can see that the enhancement in the subjective quality of images of the proposed method is more significant than the enhancement in the subjective quality of images of the proposed method is more significant than the existing methods, though the proposed method does not show better performance on the PSNR gain, the poor measure of picture quality for block coded images.

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Measurement of Molecular Weights of Melamine-Urea-Formaldehyde Resins and Their Influences to Properties of Medium Density Fiberboards

  • Jeong, Bora;Park, Byung-Dae
    • Journal of the Korean Wood Science and Technology
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    • v.44 no.6
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    • pp.913-922
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    • 2016
  • This study attempted to measure molecular weight (MW) of melamine-urea-formaldehyde (MUF) resins prepared by two different synthesis methods: the one-step MUF resins were synthesized in one batch procedure, while the two-step MUF resins were prepared by a physical mixing of urea-formaldehyde (UF) resin with melamine-formaldehyde (MF) resin that had been synthesized in a separate procedure. The properties of medium density fiberboard (MDF) panels bonded with two types of MUF resins were also investigated. MWs of these MUF resins were measured using gel permeation chromatography (GPC). In addition, this study measured the MWs of one-step MUF resin during its synthesis procedure. The performance of two types of MUF resins was evaluated by determining properties of MDF panels prepared in laboratory. As the synthesis procedure progressed, both number average MW ($M_n$) and weight average MW ($M_w$) of one-step MUF resin gradually increased, while the polydispersity index (PDI) decreased. And low Mw species of the resin predominantly decreased as the synthesis step progressed. The one-step MUF resin showed greater $M_n$ and $M_w$ than those of the two-step ones even though the PDI values of both resins were very similar each other. As expected, the one-step MUF resin resulted in better properties of MDF panels than those of two-step resins. In particular, the one-step MUF resin provided better internal bond (IB) strength and thickness swelling (TS) with MDF panels than those of two-step ones, indicating better water resistance of the one-step resin. These results suggest that the preparation method of MUF resins have a great impact on the MW and final panel properties.

Damage Detection of Railroad Tracks Using Piezoelectric Sensors (압전센서를 이용하는 철로에서의 손상 검색 기술)

  • Yun Chung-Bang;Park Seung-Hee;Inman Daniel J.
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2006.04a
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    • pp.240-247
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    • 2006
  • Piezoelectric sensor-based health monitoring technique using a two-step support vector machine (SYM) classifier is discussed for damage identification of a railroad track. An active sensing system composed of two PZT patches was investigated in conjunction with both impedance and guided wave propagation methods to detect two kinds of damage of the railroad track (one is a hole damage of 0.5cm in diameter at web section and the other is a transverse cut damage of 7.5cm in length and 0.5cm in depth at head section). Two damage-sensitive features were extracted one by one from each method; a) feature I: root mean square deviations (RMSD) of impedance signatures and b) feature II: wavelet coefficients for $A_0$ mode of guided waves. By defining damage indices from those damage-sensitive features, a two-dimensional damage feature (2-D DF) space was made. In order to minimize a false-positive indication of the current active sensing system, a two-step SYM classifier was applied to the 2-D DF space. As a result, optimal separable hyper-planes were successfully established by the two-step SYM classifier: Damage detection was accomplished by the first step-SYM, and damage classification was also carried out by the second step-SYM. Finally, the applicability of the proposed two-step SYM classifier has been verified by thirty test patterns.

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Blood Pressure Measurement using the Modified Step-wise Deflation Method (개선된 계단 배기 방법을 이용한 혈압 측정)

  • Oh, Hong-Sic;Lee, Jong-Shill;Chee, Young-Joon;Kim, In-Young
    • Journal of Biomedical Engineering Research
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    • v.31 no.5
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    • pp.351-358
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    • 2010
  • In the automatic non-invasive blood pressure measurement device, the oscillometric method iswidely used. In the oscillometric method, the step-wise deflation has the advantage of the robustness for the motion artifacts than the linear deflation method. But it has the disadvantage of its longer measurement time because we need to detect two or more pulses in a certain cuff pressure step. In this study, we suggest the modified step-wise deflation method to overcome this limitation while maintaining the general concept of step-wise deflation. Using one valid pulse in each step and the deflating valve control during the diastolic period, the measurement time could be reduced. In order to verify the accuracy of the proposed algorithm, we compared the blood pressure values from the suggested method and the blood pressure values from the conventional auscultation method. The mean and standard deviation were -0.50${\pm}$5.3mmHg and 2.08${\pm}$4.75mmHg, for systolic and diastolic blood pressure respectively. The measurement time can be reduced up to the half of conventional step-wise deflation method.

A Method for Evaluating Electric Shock Hazards Based on Human Body Current (인체전류를 기반으로 하는 감전의 위험성 평가방법)

  • Lee, Bok-Hee;Yoo, Yang-Woo;Choi, Jong-Hyuk
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.25 no.6
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    • pp.108-114
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    • 2011
  • In order to mitigate the possible hazards from electric shock due to the touch and step voltages, the high resistivity material such as gravel is often spread on the earth's surface in substations. When the grounding electrode is installed in two-layer soil structures, the surface layer soil resistivity is different with the resistivity of the soil contacted with the grounding electrodes. The design of large-sized grounding systems is fundamentally based on assuring safety from dangerous voltages within a grounding grid area. The performance of the grounding system is evaluated by tolerable touch and step voltages. Since the floor surface conditions near equipment to be grounded are changed after a grounding system has been constructed, it may be difficult to determine the tolerable touch and step voltage criteria. In this paper, to propose an accurate and convenient method for evaluating the protective performance of grounding systems, the propriety of the method for evaluating the current flowing through the human body around on a counterpoise buried in two-layer soils is presented. As a result, it is reasonable that the grounding system performance would be evaluated by measuring and analyzing the current flowing through the human body based on dangerous voltages such as the touch or step voltages and the contact resistance between the ground surface and feet.

Effects of Crystallization Behavior on Microwave Dielectric Properties of CaMgSi2O6 Glass-Ceramics

  • Choi, Bo Kyeong;Kim, Eung Soo
    • Journal of the Korean Ceramic Society
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    • v.50 no.1
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    • pp.70-74
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    • 2013
  • Dependence of microwave dielectric properties on the crystallization behaviors of $CaMgSi_2O_6$ (diopside) glass-ceramics was investigated with different heat treatment methods (one and/or two-step). The crystallization behaviors of the specimens, crystallite size and degree of crystallization, were evaluated by differential thermal analysis (DTA), scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis by combined Rietveld and reference intensity ratio (RIR) methods. With an increase in heattreatment temperature, the dielectric constant (K) and the quality factor (Qf) increased due to the increase of the crystallite size and degree of crystallization. The specimens heat-treated by the two-step method had a higher degree of crystallization than the specimens heat-treated by the one-step method, which induced improvement in the quality factor (Qf) of the specimens.

Characterizations of Two-step Matrix Application Procedures for Imaging Mass Spectrometry

  • Shimma, Shuichi
    • Mass Spectrometry Letters
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    • v.6 no.1
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    • pp.21-25
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    • 2015
  • In this paper, I describe the importance of matrix spraying conditions in imaging mass spectrometry (IMS) to obtain successful imaging results. My developed matrix application methodology, which is a "two-step matrix application" sequentially combined with matrix sublimation and spraying matrix solution can provide high reproducibility and high ion yield compared with a conventional direct spraying method. However, insufficient IMS results were obtained occasionally despite the two-step method. Therefore, I wanted to characterize the methodology to continuously provide high quality data. According to my results, the sublimation time was not a strict parameter, and the most important step was the first spraying condition. This means that the extraction conditions from the tissue section and co-crystallization of the matrix were the most important factors.