• Title/Summary/Keyword: Magnitude factor

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Damping modification factor of pseudo-acceleration spectrum considering influences of magnitude, distance and site conditions

  • Haizhong Zhang;Jia Deng;Yan-Gang Zhao
    • Earthquakes and Structures
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    • v.25 no.5
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    • pp.325-342
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    • 2023
  • The damping modification factor (DMF) is used to modify the 5%-damped response spectrum to produce spectral values that correspond to other necessary damping ratios for seismic design. The DMF has been the subject of numerous studies, and it has been discovered that seismological parameters like magnitude and distance can have an impact on it. However, DMF formulations incorporating these seismological parameters cannot be directly applied to seismic design because these parameters are not specified in the present seismic codes. The goal of this study is to develop a formulation for the DMF that can be directly applied in seismic design and that takes the effects of magnitude, distance, and site conditions into account. To achieve this goal, 16660 ground motions with magnitudes ranging from 4 to 9 and epicentral distances ranging from 10 to 200 km are used to systematically study the effects of magnitude, distance, and site conditions on the DMF. Furthermore, according to the knowledge that magnitude and distance affect the DMF primarily by changing the spectral shape, a spectral shape factor is adopted to reflect influences of magnitude and distance, and a new formulation for the DMF incorporating the spectral shape factor is developed. In comparison to the current formulations, the proposed formulation provides a more accurate prediction of the DMF and can be employed directly in seismic design.

A Novel Detection Algorithm for Instantaneous Voltage Sag Corrector Using Series Compensator

  • Lee, Sang-Hoon;Choi, Jae-Ho
    • Proceedings of the KIPE Conference
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    • 2001.10a
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    • pp.502-507
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    • 2001
  • This paper proposes a novel detection algorithm of faulted voltages under the unbalanced condition. To quantify the standard of unbalance under the faulted conditions, the 3-phase unbalanced voltages are decomposed into two balanced 3-phase symmetrical components of the positive and negative sequence voltages, which is defined by the magnitude factor (MF) and unbalance factor (MF). It is analyzed that MF and UF values are given as the dc constant values even though unbalance condition. This paper also proposes the control scheme of the instantaneous voltage sag corrector based on this detection algorithm. The validity of the proposed algorithm is verified through the EMTDC simulation and experiments.

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Voltage Sag Detection Algorithm for Instantaneous Voltage Sag Corrector

  • Lee, Sang-Hoon;Choi, Jae-Ho
    • Journal of Power Electronics
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    • v.2 no.3
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    • pp.162-170
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    • 2002
  • Voltage sag detection algorithm for voltage sag corrector is proposed in this paper. To quantify the standard of voltage unbalance under the faulted conditions, the 3-phase unbalanced voltages are decomposed into two balanced 3-phase symmetrical components of the positive and negative sequence voltages, which is defined by the magnitude factor (MF) and unbalance factor (UF). It is analyzed that MWF and UF values are given as the dc constant values even though under the voltage unbalance condition. This paper also proposes the control scheme of the instantaneous voltage sag corrector based on this detection algorithm. The validity of the proposed algorithm is verified through the EMTDC simulation and experiments.

Analysis of Insulation Condition in High Voltage Motor Stator Windings Following Cleaning and Insulation Reinforcement (세척과 절연보강에 따른 고압전동기 고정자 권선의 절연상태 분석)

  • Kim, Hee-Dong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.25 no.6
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    • pp.474-480
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    • 2012
  • Diagnostic tests were performed on two high voltage(HV) motor stator windings. These tests included the measurement of insulation resistance, polarization index, AC current, dissipation factor($tan{\delta}$) and partial discharge(PD) magnitude. Surface contamination of HV motor stator windings has an effect on the AC current and $tan{\delta}$. When the stator windings were finished cleaning and insulation reinforcement, the increase rate of AC current(${\Delta}I$) and dissipation factor(${\Delta}tan{\delta}$) were very small compared to those before cleaning. However, the PD magnitude remained the same. These tests show that cleaning and insulation reinforcement of HV motor stator windings can reduce the insulation failure.

Analysis of Insulation Quality in Large Generator Stator Windings

  • Kim, Hee-Dong;Kong, Tae-Sik;Ju, Young-Ho;Kim, Byong-Han
    • Journal of Electrical Engineering and Technology
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    • v.6 no.3
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    • pp.384-390
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    • 2011
  • To evaluate the condition of stator winding insulation in generators that have been operated for a long period of time, diagnostic tests were performed on the stator bars of a 500 MW, 22 kV generator under accelerated thermal and electrical aging procedures. The tests included measurements of AC current (${\Delta}I$), dissipation factor ($tan{\delta}$), partial discharge (PD) magnitude, and capacitance (C). In addition, the AC current test was performed on the stator winding of a 350 MW, 24 kV generator under operation to confirm insulation deterioration. The values of ${\Delta}I$, ${\Delta}tan{\delta}$, and PD magnitude in one stator bar indicated serious insulation deterioration. In another stator bar, the ${\Delta}I$ measurements showed that the insulation was in good condition, whereas the values of ${\Delta}tan{\delta}$ and PD magnitude indicated an incipient stage of insulation deterioration. Measurements of ${\Delta}I$ and PD magnitude in all three phases (A, B, C) of the remaining generator stator windings showed that they were in good condition, although the ${\Delta}tan{\delta}$ measurements suggested that the condition of the insulation should be monitored carefully. Overall analysis of the results suggested that the generator stator windings were in good condition. The patterns of PD magnitude in all three phases (A, B, C) were attributed to internal discharge.

Risk Factors of Breast Cancer (유방암의 위험요인)

  • Chung, Bok-Yae;Byun, Hye-Sun;Kim, Kyung-Duck;Kim, Kyung-Hye
    • Asian Oncology Nursing
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    • v.8 no.2
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    • pp.120-127
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    • 2008
  • Purpose: The purpose of this study was secondary analysis to explore about risk factors with breast cancer on a basis of primary literature. Methods: This study was searched articles by using CINAHL, MEDLINE, Riss4u, Internet website regarding breast cancer. This study searched for the journal published in Korea and foreign countries from 2000 to 2008, about risk factors of breast cancer. This study was reviewed 42 articles (5 experimental study, 35 survey, 1 qualitative study, 1 report) suitable for the research objectives. Results: Magnitude of risk breast cancer (++) was age, geographic region, family history, mutations in BRCA1, BRCA2 genes and in other penetrance genes, radiation, history of benign breast disease, late age of menopause, early age of menarch, nulliparity and older age at first birth, high mammographic breast density, high insulin-like growth factor 1 level. Magnitude of risk factor (+) was hormone replacement therapy, oral contraceptives use, obesity, tall stature, alcohol consumption, high prolactin level, high saturated fat and well-done meat intake, polymorphisms in low penetrance gene, high socioeconomic status. Conclusion: A breast cancer screening protocol according to magnitude of risk factors is needed for disease prevention. The nurses need to educate and counsel women with risk factors of breast cancer.

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Bearing capacity factor Nγ for a rough conical footing

  • Khatri, Vishwas N.;Kumar, Jyant
    • Geomechanics and Engineering
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    • v.1 no.3
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    • pp.205-218
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    • 2009
  • The bearing capacity factor $N_{\gamma}$ is computed for a rough conical footing placed over horizontal ground surface. The axisymmetric lower bound limit analysis formulation, in combination with finite elements and linear programming, proposed recently by the authors is used in this study. The variation of $N_{\gamma}$ with cone apex angle (${\beta}$), in a range of $30^{\circ}-180^{\circ}$, is obtained for different values of ${\phi}$; where ${\phi}$ is soil friction angle. For ${\phi}<30^{\circ}$, the magnitude of $N_{\gamma}$ is found to decrease continuously with an increase in ${\beta}$ from $30^{\circ}$ to $180^{\circ}$. On the other hand, for ${\phi}>30^{\circ}$, the minimum magnitude of $N_{\gamma}$ is found to occur generally between ${\beta}=120^{\circ}$ and ${\beta}=150^{\circ}$. In all the cases, it is noticed that the magnitude of $N_{\gamma}$ becomes maximum for ${\beta}=30^{\circ}$. For a given diameter of the cone, the area of the plastic zone reduces generally with an increase in ${\beta}$. The obtained values of $N_{\gamma}$ are found to compare quite well with those available in literature.

The Response of the Structure with the Damage Curve (손상곡선에 의한 구조물의 거동파악)

  • Lee, Sang-Ho;Song, Hyun-Seop
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.9 no.1
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    • pp.189-196
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    • 2005
  • The effects of the impulse and the magnitude of the impulsive loads to the responses of the structure are analyzed with the safety criteria established with the peak load and impulse ratio. It is shown for the loadings with short duration that the impulse is dominant factor for the damage of the structures due to the inertial effect. On the other hand the magnitude of the load is dominant factor for the load with long duration due to the duration time long enough for the loads to overcome the inertia force. It is also shown that the peak particle velocity and the peak particle acceleration of the foundation have the same influences as the impulse and the magnitude of the loads do to the structures.

INFLUENCE FACTOR-BASED RISK ASSESSMENT METHODOLOGY FOR CONSTRUCITON

  • Hyunsoo Kim;Hyunsoo Lee;Moonseo Park;Kwang-pyo Lee
    • International conference on construction engineering and project management
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    • 2009.05a
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    • pp.1231-1236
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    • 2009
  • Many work-related risk factors can cause construction site hazards. Therefore, safety management begins with measuring the magnitude of risk involved in a project. This study proposes a methodology for risk assessment of major trades at a particular construction site. To assess risk, this methodology integrates hazard severity and frequency, and their magnitude is calculated based on actual work-site hazards. This methodology also considers the influence factors that affect the frequency of work-related hazards. To select the appropriate influence factors, a two step approach is deployed. First, the predominant factors are identified through a literature review. Second, a selective process filters out the influence factors that are difficult to analyze quantitatively, and these extracted factors are weighted using expert surveys. Finally, the factors are combined and a quantitative risk assessment methodology is proposed.

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Evaluating design alternatives based on magnitude estimation (Magnitude Estimation기법을 이용한 설계대안의 평가)

  • 한성호;정의승;정무영;박성준;곽지영;최필성
    • Journal of the Ergonomics Society of Korea
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    • v.12 no.2
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    • pp.3-13
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    • 1993
  • A psychophysical measurement technique called "magnitude estimation" was used to evaluate several interior design alternatives for a high speed train. Pas- senger activity, seat direction, and passenger age were manipulated by using a three factor within-subjects experimental design. During the experiment, two dependent measures, a line length and a numerical estimate for each alternative design were collected to validate the experimental procedures. The results showed that pasnger seats arranged in the same direction as the running direction of the train was favored nine times more than the opposite. Also, the subjects preferred listening to music in a coach train to the other activities such as reading newspaper, watching a movie, and resting. This paper demonstrates that a psychophysical technique can be sued in the design of a development process, especially when it is difficult to quantify design variables such as subjective opinion or preference, etc.

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