• 제목/요약/키워드: Sampled-data control

검색결과 255건 처리시간 0.045초

진동의 주파수분석을 통한 결함 식별 - 회전기계를 중심으로- (Defect Identification through Frequency Analysis of Vibration -In Case of Rotary Machine_)

  • 정윤성;왕지남;김광섭
    • 한국정밀공학회지
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    • 제12권11호
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    • pp.82-90
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    • 1995
  • This paper pressents a condition-based maintenance (CBM) method through bibration analysis. The well known frequency analysis is employed for performing machine fault diagnosis. The statistical control chart is also applied for analyzing the trend of the bearing wear. Vibration sensors are attached to prototype machine and signals are continuously monitored. The sampled data are utilized to evaluate how well the fast fourier transform(FFT) and the statistical control chart techniques could be used to identify defects of machine and to analyze the machine degradation. Experimental results show that the propowed approach could classify every mal-function and could be utilized for real machine diagnosis system.

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대학생의 금연 행위에 대한 연구- 계획된 행위이론, 자기효능, 건강통제위와의 관계 고찰을 중심으로 - (A Study of the Smoking Cessation Behavior of University Student- Based on the Theory of Planned Behavior, Self Efficacy, Health Locus of Control -)

  • 안혜영
    • Child Health Nursing Research
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    • 제7권3호
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    • pp.371-382
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    • 2001
  • This study was conducted to investigate correlation theory of planned behavior, self efficacy and health locus of control about smoking cessation behavior for university student. We sampled 204 university student smokers using questionnaires and analyzed the data using Pearson correlation coefficient. The results of this study were as follows : 1. There were significant positive correlation between theory of planned behavior(intention : r=.215, p=.005, attitude : r=.160, p=.025, perceived behavior control : r=.298, p=.000) and self efficacy. 2. There were significant positive correlation between theory of planned behavior(attitude : r=.228, p=.002) and internal health locus of control. There were significant positive correlation between theory of planned behavior(attitude : r=.203, p=.004, subjective norm : r=.141, p=.047) and external health locus of control. There were significant negative correlation between theory of planned behavior(perceived behavior control : r=-.152, p=.034) and accidental health locus of control. This study has shown a correlation between theory of planned behavior and self efficacy and health locus of control. As a result of these findings, I suggest to develop the intervention program for smoking cessation.

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복소유전률 측정장치의 연구개발 - 컴퓨터제어 복소유전률 측정장치 - (A study on the computer-controlled measuring device of complex dielectric constant)

  • 남징락;엄상오;강대하
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1993년도 하계학술대회 논문집 B
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    • pp.1206-1208
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    • 1993
  • This paper is to study and realize a measuring device for complex dielectric constants. The device is consisted in order of interface unit, external RAM, programmable counter, D/A converter, measuring circuit, Sample & Hold circuit, A/D converter and related control circuits. Various excitation waves are digitalized and sent to the 4096 static RAM by personal computer. These data saved in the RAM are converted to analog excitation waves through D/A converter. The frequency of excitation wave is depend on the read-out speed of the RAM according to clock pulses. Such generated waves are applied to dielectrics under test and their responses are sampled and converted to digital data through A/D converter. The computer takes the digital data and calculates finally the complex dielectric constants. The frequencies for Measurement ranges from 0.04 Hz to 10 kHz.

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PC Skill-Reporting System을 활용한 심폐소생술 교육이 간호학생의 지식, 자기효능감, 술기수행능력에 미치는 효과 (Effects of Cardiopulmonary Resuscitation Education Using a PC Skill-Reporting System on the Knowledge, Self-Efficacy and Skill Performance Ability of Nursing Students)

  • 김란;채민정
    • 보건의료산업학회지
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    • 제9권1호
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    • pp.133-144
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    • 2015
  • The Purpose of this study was to identify the educational effects of cardiopulmonary resuscitation using a PC skill-reporting system on the knowledge, Self-efficacy and skill performance ability of nursing students. The Participants were 57 nursing students from G metropolitan city, an experimental group of 29 subjects, and a control group of 28 students who were randomly sampled. Data were collected from 3 to 12 July of, 2013, and theory education and skill exposure programs for the experimental and control groups were conducted for 60 min. three times a week. The, PC skill-reporting system was used only with the experimental group. The collected data were analyzed with SPSS/WIN version 20.0 using ${\chi}^2$-tests, Fisher's exact probability tests, paired t-tests and t-tests. In the comparison of the two groups, the knowledge(t=-2.39, p=.022), self-efficacy (t=-3.45, p<.001) and skill performance ability(t=-2.52, p=.012) of the experiment group were significantly higher than those of the control group. Therefore, the adoption of instructional methods using a PC skill-reporting system is required to maximize the effects of cardiopulmonary resuscitation instruction.

Energy Bounding Algorithm for Stable Haptic Interaction

  • Kim, Jong-Phil;Ryu, Je-Ha
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2003년도 ICCAS
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    • pp.2765-2770
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    • 2003
  • This paper introduces a novel control algorithm, energy bounding algorithm, for stable haptic interaction. The energy bounding algorithm restricts energy generated by zero-order hold within consumable energy by physical damping that is energy consumption element in the haptic interface. The passivity condition can always be guaranteed by the energy bounding algorithm. The virtual coupling algorithm restricts the actuator force with respect to the penetration depth and restricts generated energy. In contrast, energy bounding algorithm restricts the change of actuator force with respect to time and restricts generated energy by zero-order hold. Therefore, much stiffer contact simulation can be implemented by the energy bounding algorithm. Moreover, the energy bounding algorithm doesn’t is not computationally intensive and the implementation of it is very simple.

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Discrete Representation Method of Nonlinear Time-Delay System in Control

  • Park, Ji-Hyang;Chong, Kil-To
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2003년도 ICCAS
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    • pp.327-332
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    • 2003
  • A new discretization method for nonlinear system with time-delay is proposed. It is based on the well-known Taylor series expansion and the zero-order hold (ZOH) assumption. We know that a discretization of linear system can be obtained with the ZOH assumption and within the sampling interval. A similar line of thinking is available in nonlinear case. The mathematical structure of the new discretization method is explored and under the structure, the sampled-data representation of nonlinear system including time-delay is computed. Provided that the discrete form of the single input nonlinear system with time-delay is derived, this result is easily extended to nonlinear system with multi-input time-delay. For simplicity two inputs are considered in this study. It is enough to generalize that of multiple inputs. Finally, the time-discretization of non-affine nonlinear system with time-delay is investigated for apply all nonlinear system

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Taylor series를 이용한 시변 지연 입력을 갖는 비선형 시스템의 이산화 (Time Discretization of Nonlinear System with Variable Time-delay Input Using Taylor Series Expansion)

  • 최형조;박지향;이수영;정길도
    • 제어로봇시스템학회논문지
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    • 제11권1호
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    • pp.1-8
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    • 2005
  • A new discretization algorithm for nonlinear systems with delayed input is proposed. The algorithm is represented by Taylor series expansion and ZOH assumption. This method is applied to the sampled-data representation of a nonlinear system with the time-delay input. Additionally, the delay in input is time varying and its amplitude is bounded. The maximum time-delay in input is assumed to be two sampling periods. The mathematical expressions of the discretization method are presented and the ability of the algorithm is tested for some of the examples. The computer simulation proves the proposed algorithm discretizes the nonlinear system with the variable time-delay input accurately.

아동성폭력 예방을 위한 행동기술훈련의 효과에 관한 연구 (The Effectiveness of Behavioral Skill Training for the Prevention of Child Sexual Abuse)

  • 손승아
    • 아동학회지
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    • 제13권2호
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    • pp.189-201
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    • 1992
  • The purpose of this study was to investigate the effectiveness of teaching personal safety skills for prevention of potential child sexual abuse in Korean society. The subjects of this study were 80 first grade female students, sampled from elementary schools in Seoul. The instruments of this study were the Personal Safety Questionnaire (PSQ) and 'What if' Situations Test (WIST) modified by the present researcher. The t-test and Pearson's correlation coefficient were applied to analyze the data of this study. The results of the analysis were (1) after the Behavioral Skills Training, the children of the training group showed a higher level of knowledge about child sexual abuse than the control group. (2) After the Behavioral Skills Training, the children of the training group showed more adequate self-defensive skills than the control group when they faced situations of possible child sexual abuse. (3) The higher the level of knowledge about child sexual abuse, the more adequate self-defensive skills in situations of child sexual abuse. These results supported the effectiveness of Behavioral Skills Training as preventive education on potential child sexual abuse.

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AI기법을 이용한 멀티채널 심전도신호의 패턴인식 알고리즘 (An algorithm for pattern recognition of multichannel ECG signals using AI)

  • 신건수;이병채;황선철;이명호
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
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    • pp.575-579
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    • 1990
  • This paper describes an algorithm that can efficiently analyze the multichannel ECG signal using the frame. The input is a set of significant features (points) which have been extracted from an original sampled signal by using the split-and-merge algorithm. A signal from each channel can be hierarchical ADN/OR graph on the basis of the priori knowledge for ECG signal. The search mechanisms with some heuristics and the mixed paradigms of data-driven hypothesis formation are used as the major control mechanisms. The mutual relations among features are also considered by evaluating a score based on the relational spectrum. For recognition of morphologies corresponding to OR nodes, an hypothesis modification strategy is used. Other techniques such as instance, priority update of prototypes, and template matching facility are also used. This algorithm exactly recognized the primary points and supporting points from the multichannel ECG signals.

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Robust Discretization of LTI Systems with Polytopic Uncertainties and Aperiodic Sampling

  • Lee, Dong Hwan;Park, Jin Bae;Joo, Young Hoon
    • Journal of Electrical Engineering and Technology
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    • 제10권3호
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    • pp.1255-1263
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    • 2015
  • In the previous work, the authors studied the problem of robust discretization of linear time-invariant systems with polytopic uncertainties, where linear matrix inequality (LMI) conditions were developed to find an approximate discrete-time (DT) model of a continuous-time (CT) system with uncertainties in polytopic domain. The system matrices of obtained DT model preserved the polytopic structures of the original CT system. In this paper, we extend the previous approach to solve the problem of robust discretization of polytopic uncertain systems with aperiodic sampling. In contrast with the previous work, the sampling period is assumed to be unknown, time-varying, but contained within a known interval. The solution procedures are presented in terms of unidimensional optimizations subject to LMI constraints which are numerically tractable via LMI solvers. Finally, an example is given to show the validity of the proposed techniques.