• Title/Summary/Keyword: Difference Values

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Fault Detection and Identification of Induction Motors with Current Signals Based on Dynamic Time Warping

  • Bae, Hyeon;Kim, Sung-Shin;Vachtsevanos, George
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • 제7권2호
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    • pp.102-108
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    • 2007
  • The issues of preventive and condition-based maintenance, online monitoring, system fault detection, diagnosis, and prognosis are of increasing importance. This study introduces a technique to detect and identify faults in induction motors. Stator currents were measured and stored by time domain. The time domain is not suitable for representing current signals, so wavelet transform is used to convert the signal; onto frequency domain. The raw signals can not show the significant feature, therefore difference values are applied. The difference values were transformed by wavelet transform and the features are extracted from the transformed signals. The dynamic time warping method was used to identify the four fault types. This study describes the results of detecting fault using wavelet analysis.

도시주부의 가치유형과 계획행동유형 및 가정생활만족도 (Value Patterns Planning Styles and Family Life Satisfaction of Urban Homemakers)

  • 황덕순
    • 가정과삶의질연구
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    • 제14권4호
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    • pp.203-218
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    • 1996
  • This study analyzed the relationships among the components of home management system. Through this it make to explain relationship between values and planning exactly and partially to test empirically system model to home management 650 housewives were adapted as data. Cluster analysis \chi$2 and ANOVA were used as statistical analysis. The resultes are summarized as follows 1) Goal-centered planning level was higher than that of resource-centered By 2 plannings subjects were classified into 4 planning styles : active morphogenic resource-reorganized demand-reorganized passive morphostatic style. 2) A difference between terminal value patterns and planning styles was no significant but a difference between instrumental value patterns and planning styles was significant. Family life satisfaction showed significant differences by not value patterns but planning styles. Because of high family life satisfaction as output of management active morphogenic style was successful. For succ ssful planning, it was suggested that homemarkers should possess values related broadminded loving and forgiving.

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Thermoelastic analysis for a slab made of a thermal diode-like material

  • Darwish, Feras H.;Al-Nimr, Mohammad A.;Hatamleh, Mohammad I.
    • Structural Engineering and Mechanics
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    • 제53권4호
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    • pp.645-659
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    • 2015
  • This research investigates the thermoelastic transient behavior of a thermally loaded slab made of a thermal diode-like material which has two directional thermal conductivity values (low and high). Finite difference analysis is used to obtain the elastic response of the slab based on the temperature solutions. It is found that the rate of heat transfer through the thickness of the slab decreases with reducing the ratio between the low and high thermal conductivity values (R). In addition, reducing R makes the slab less responsive to the thermal load when heated from the direction associated with the low thermal conductivity value.

한국인 아동의 측모에 관한 연구 (THE STUDY FOR THE PROFILES OF MIXED DENTITION)

  • 박태원
    • 치과방사선
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    • 제8권1호
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    • pp.17-21
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    • 1978
  • The study was to analyze on the hard and soft tissue profiles in mixed dentition. The subject consisted of 100 males and 100 females from 9 to 12 years of age and with a normal occlusion and acceptable profiles. On the basis of SnH line and SnV line, the author traced all the cephalograms and calculated the mean value and standard deviation in each measuring category and evaluated the sexual difference, the proper limit of development. The obtained results were as follows; 1. Individual variations of the lower facial part were larger the upper facial part in depth and height. 2. Sexual difference of lower facial part was significant in depth and height. 3. All the measured values to the SnH and SnV line were larger in male than in female but revealed resemblance in the profilogram. 4. The measured values of the region of nose, upper lip and point A showed stable tendency.

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개선된 굽힘 시험장치를 이용한 스프링백 비의 측정 (Measurement of Springback Ratio Using a Bend Rig)

  • 김용우;공성일;남진영
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2002년도 춘계학술대회 논문집
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    • pp.410-415
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    • 2002
  • A winding bend rig is designed to overcome the drawbacks of the conventional bend rig for measuring springback ratio of a strip or plate. Using the present bend rig, springback ratios are measured and they are compared with ones that obtained by using simple beam theory and tensile test. Theoretically, there should be no difference between the two values as far as the simple beam theory holds true for the bending test. But, within the scope of our tests, there is a difference of 5% between the two values since the specimen under bend test is subjected to a transverse shear force and friction force on the surface of the specimen.

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쓰레기종량제에 따른 쓰레기의 특성 및 발열양 분석 (The Characteristics and Heating Values Analysis of Municipal Solid Wastes according)

  • 문추조;정순형;이태호
    • 환경위생공학
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    • 제10권3호
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    • pp.29-34
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    • 1995
  • This study was on the characteristics and heating values analysis of municipal solid wastes according to the volume- rate garbage collection system in Busan. Each waste sample was analyzed to obtain physical composition, proximate analysis, heating value, chemical composition. And the heating value were compared with those of the past waste collection system. The average physical composition of A.P.T. area was food waste 54.0~65.7% , while that of common residence was food waste 57.9~61.2% . The density of solid waste were largely different for site and the highest densities of waste was $399.6kg/m^{3}$ from Market. The low heating value of waste from residence site was 996.9kca1/kg~1, 238.1 kcal/kg which was lower than 1, 000kcal/kg~1, 800kca1/kg of the past wastes. These difference was mainly due to the difference of moisture content and the amount of vegetables.

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Constructing Simultaneous Confidence Intervals for the Difference of Proportions from Multivariate Binomial Distributions

  • Jeong, Hyeong-Chul;Kim, Dae-Hak
    • 응용통계연구
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    • 제22권1호
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    • pp.129-140
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    • 2009
  • In this paper, we consider simultaneous confidence intervals for the difference of proportions between two groups taken from multivariate binomial distributions in a nonparametric way. We briefly discuss the construction of simultaneous confidence intervals using the method of adjusting the p-values in multiple tests. The features of bootstrap simultaneous confidence intervals using non-pooled samples are presented. We also compute confidence intervals from the adjusted p-values of multiple tests in the Westfall (1985) style based on a pooled sample. The average coverage probabilities of the bootstrap simultaneous confidence intervals are compared with those of the Bonferroni simultaneous confidence intervals and the Sidak simultaneous confidence intervals. Finally, we give an example that shows how the proposed bootstrap simultaneous confidence intervals can be utilized through data analysis.

DTW를 이용한 유도전동기 베어링 및 회전자봉 고장진단 (Fault Detection and Diagnosis of Faulty Bearing and Broken Rotor Bar of Induction Motors Based on Dynamic Time Warping)

  • 이재현;배현
    • Journal of Advanced Marine Engineering and Technology
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    • 제31권1호
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    • pp.95-102
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    • 2007
  • The issues of preventive and condition-based maintenance, online monitoring, system fault detection, diagnosis and prognosis are of increasing importance. This study introduces a technique to detect and identify faults in induction motors. Stator currents were measured and stored by time domain. The time domain is not suitable for representing current signals, so wavelet transform is used to convert the signals onto frequency domain. The raw signals can not show the significant feature, therefore difference values between the signal of the health conditions and that of the fault conditions are applied. The difference values were transformed by wavelet transform and the features are extracted from the transformed signals. The dynamic time warping method was used to identify the fault type. This study describes the results of detecting fault using wavelet analysis.

Students' Perspectives (Stream-Wise) of Parameters Affecting Education Quality in an Affiliated Undergraduate Engineering Institution

  • Kumari, Neeraj
    • Asian Journal of Business Environment
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    • 제4권3호
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    • pp.13-18
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    • 2014
  • Purpose - This study examines students' perspectives (stream-wise) of parameters affecting education quality in an affiliated undergraduate engineering institution in NCR, Haryana. Research design, data, and methodology - This study involves descriptive research and data collection using a structured questionnaire based on the Likert scale. The sample comprises 500 student respondents. For data analysis, an f-test was performed using high quality SPSS software. Results - For "Selection" and "Personality Development & Industry Exposure," the analysis of variance revealed a statistical difference between the mean values of the groups. Whereas, for "Academic Excellence," "Infrastructure," "Placements," and "Management & Administration," the analysis of variance revealed no statistical difference between the mean values of the groups. Conclusions - Students' perceptions about the "Selection" and "Personality Development & Industry Exposure" change according to the various specializations they opt for in their undergraduate engineering education in Haryana. Whereas, for "Academic Excellence," "Infrastructure," "Placements," and "Management & Administration," the perceptions of the students do not vary because of the different specializations they have opted for in their undergraduate engineering education.

EIGENVALUES FOR THE SEMI-CIRCULANT PRECONDITIONING OF ELLIPTIC OPERATORS WITH THE VARIABLE COEFFICIENTS

  • Kim, Hoi-Sub;Kim, Sang-Dong;Lee, Yong-Hun
    • 대한수학회지
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    • 제44권3호
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    • pp.627-645
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    • 2007
  • We investigate the eigenvalues of the semi-circulant preconditioned matrix for the finite difference scheme corresponding to the second-order elliptic operator with the variable coefficients given by $L_vu\;:=-{\Delta}u+a(x,\;y)u_x+b(x,\;y)u_y+d(x,\;y)u$, where a and b are continuously differentiable functions and d is a positive bounded function. The semi-circulant preconditioning operator $L_cu$ is constructed by using the leading term of $L_vu$ plus the constant reaction term such that $L_cu\;:=-{\Delta}u+d_cu$. Using the field of values arguments, we show that the eigenvalues of the preconditioned matrix are clustered at some number. Some numerical evidences are also provided.