• Title/Summary/Keyword: Level probability

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Reliability index for non-normal distributions of limit state functions

  • Ghasemi, Seyed Hooman;Nowak, Andrzej S.
    • Structural Engineering and Mechanics
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    • v.62 no.3
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    • pp.365-372
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    • 2017
  • Reliability analysis is a probabilistic approach to determine a safety level of a system. Reliability is defined as a probability of a system (or a structure, in structural engineering) to functionally perform under given conditions. In the 1960s, Basler defined the reliability index as a measure to elucidate the safety level of the system, which until today is a commonly used parameter. However, the reliability index has been formulated based on the pivotal assumption which assumed that the considered limit state function is normally distributed. Nevertheless, it is not guaranteed that the limit state function of systems follow as normal distributions; therefore, there is a need to define a new reliability index for no-normal distributions. The main contribution of this paper is to define a sophisticated reliability index for limit state functions which their distributions are non-normal. To do so, the new definition of reliability index is introduced for non-normal limit state functions according to the probability functions which are calculated based on the convolution theory. Eventually, as the state of the art, this paper introduces a simplified method to calculate the reliability index for non-normal distributions. The simplified method is developed to generate non-normal limit state in terms of normal distributions using series of Gaussian functions.

Anger, Anger Expression Types, Problem Behaviors, and Suicide Probability in Adolescent Women using Cluster Analysis (군집분석을 이용한 청소년기 여성의 분노, 분노표현 유형, 문제행동 및 자살 위험성)

  • Moon, So Hyun;Cho, Hun Ha
    • Women's Health Nursing
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    • v.21 no.2
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    • pp.128-138
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    • 2015
  • Purpose: This cross-sectional study was designed to identify anger-expression types of adolescent women and investigate the relationship between the identified anger-expression types and their problem behaviors and suicide probability. Methods: The participants were 942 students at two female high school located in Gwangju. The data were analyzed using descriptive statistics, cluster analysis, t-test, ANOVA, and $Scheff{\acute{e}}$ multiple comparison test. Results: Cluster analysis revealed 4 distinct anger expression types; Anger-out, Low anger expression, Anger-control, and Anger-in/out types. Female adolescent women had a higher level of trait anger or who frequently used the anger-in/out type reported internalized-externalized problem behaviors and suicide probability more frequently compared to those who frequently used the other three types of anger expression. Conclusion: Female adolescent women who had the low anger expression type and anger control type managed anger most effectively. The findings suggest the necessity of a development of the program for lowering the trait anger level and controlling the unfavorable anger expression types such as the anger-in/out.

Seismic reliability analysis of structures based on cumulative damage failure mechanism

  • Liu, Qiang;Wang, Miaofang
    • Earthquakes and Structures
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    • v.18 no.4
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    • pp.519-526
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    • 2020
  • Non-stationary random seismic response and reliability of multi-degree of freedom hysteretic structure system are studied based on the cumulative damage failure mechanism. First, dynamic Eqs. of multi-degree of freedom hysteretic structure system under earthquake action are established. Secondly, the random seismic response of a multi-degree freedom hysteretic structure system is investigated by the combination of virtual excitation and precise integration. Finally, according to the damage state level of structural, the different damage state probability of high-rise frame structure is calculated based on the boundary value of the cumulative damage index in the seismic intensity earthquake area. The results show that under the same earthquake intensity and the same floor quality and stiffness, the lower the floor is, the greater the damage probability of the building structure is; if the structural floor stiffness changes abruptly, the weak layer will be formed, and the cumulative damage probability will be the largest, and the reliability index will be relatively small. Meanwhile, with the increase of fortification intensity, the reliability of three-level structure fortification is also significantly reduced. This method can solve the problem of non-stationary random seismic response and reliability of high-rise buildings, and it has high efficiency and practicability. It is instructive for structural performance design and estimating the age of the structure.

System-Level Simulation for Efficient Displacement of Base Station Antennas for CDMA Uplink System in Urban Microcells (도심 마이크로셀에서 CDMA 시스템을 위한 효율적인 기지국 배치를 위한 모의실험)

  • Min, Seung-Wook
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.5A
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    • pp.517-525
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    • 2008
  • In this paper, we cary out system level simulations to investigate the effect of cell shape(i.e., different base station displacements in the two directions defined by the street grid) on minimizing transmitter power, interference power, and blocking probability for CDMA system in urban microcellular environments. In urban microcell, path loss to the base station depends on the orientation of the street where the mobile is located. Interference from mobile stations to the base station in the reference cell is considered up to second tier. The wrap around method is used to include the second tier interference with realistic computational complexity without reducing the accuracy of interference calculations. The investigation shows that the transmitter power, interference power, and blocking probability in a cell can be reduced by proper selection of the efficient cell shape.

Power Allocation for Opportunistic Full-Duplex based Relay Selection in Cooperative Systems

  • Zhong, Bin;Zhang, Dandan;Zhang, Zhongshan
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.9 no.10
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    • pp.3908-3920
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    • 2015
  • In this paper, performance analysis of full-duplex (FD) relay selection under decode-and-forward (DF) relaying mode is carried out by taking into account several critical factors, including the distributions of the received signal-to-noise ratio (SNR) and the outage probability of wireless links. The tradeoff between the FD and half-duplex (HD) modes for relay selection techniques is also analyzed, where the former suffers from the impact of residual self-interference, but the latter requires more channel resources than the former (i.e., two orthogonal channels are required). Furthermore, the impact of optimal power allocation (OPA) on the proposed relay-selection scheme is analyzed. Particularly, the exact closed-form expressions for outage probability of the proposed scheme over Rayleigh fading channels are derived, followed by validating the proposed analysis using simulation. Numerical results show that the proposed FD based scheme outperforms the HD based scheme by more than 4 dB in terms of coding gain, provided that the residual self-interference level in the FD mode can be substantially suppressed to the level that is below the noise power.

Fragility assessment of shear walls coupled with buckling restrained braces subjected to near-field earthquakes

  • Beiraghi, Hamid
    • Steel and Composite Structures
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    • v.33 no.3
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    • pp.389-402
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    • 2019
  • Reinforced concrete walls and buckling restrained braces are effective structural elements that are used to resist seismic loads. In this paper, the behavior of the reinforced concrete walls coupled with buckling restrained braces is investigated. In such a system, there is not any conventional reinforced concrete coupling beam. The coupling action is provided only by buckling restrained braces that dissipate energy and also cause coupling forces in the wall piers. The studied structures are 10-, 20- and 30-story ones designed according to the ASCE, ACI-318 and AISC codes. Wall nonlinear model is then prepared using the fiber elements in PERFORM-3D software. The responses of the systems subjected to the forward directivity near-fault (NF) and ordinary far-fault (FF) ground motions at maximum considered earthquake (MCE) level are studied. The seismic responses of the structures corresponding to the inter-story drift demand, curvature ductility of wall piers, and coupling ratio of the walls are compared. On average, the results show that the inter-story drift ratio for the examined systems subjected to the far-fault events at MCE level is less than allowable value of 3%. Besides, incremental dynamic analysis is used to examine the considered systems. Results of studied systems show that, the taller the structures, the higher the probability of their collapse. Also, for a certain peak ground acceleration of 1 g, the probability of collapse under NF records is more than twice this probability under FF records.

Probabilistic stability analysis of rock slopes with cracks

  • Zhu, J.Q.;Yang, X.L.
    • Geomechanics and Engineering
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    • v.16 no.6
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    • pp.655-667
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    • 2018
  • To evaluate the stability of a rock slope with one pre-exiting vertical crack, this paper performs corresponding probabilistic stability analysis. The existence of cracks is generally ignored in traditional deterministic stability analysis. However, they are widely found in either cohesive soil or rock slopes. The influence of one pre-exiting vertical crack on a rock slope is considered in this study. The safety factor, which is usually adopted to quantity the stability of slopes, is derived through the deterministic computation based on the strength reduction technique. The generalized Hoek-Brown (HB) failure criterion is adopted to characterize the failure of rock masses. Considering high nonlinearity of the limit state function as using nonlinear HB criterion, the multivariate adaptive regression splines (MARS) is used to accurately approximate the implicit limit state function of a rock slope. Then the MARS is integrated with Monte Carlo simulation to implement reliability analysis, and the influences of distribution types, level of uncertainty, and constants on the probability density functions and failure probability are discussed. It is found that distribution types of random variables have little influence on reliability results. The reliability results are affected by a combination of the uncertainty level and the constants. Finally, a reliability-based design figure is provided to evaluate the safety factor of a slope required for a target failure probability.

Can Minimum Wage Policy Increase Personal Income? -Evidence from China

  • Fan YANG;Shuang ZHANG;Ya-Hao LI
    • Journal of Wellbeing Management and Applied Psychology
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    • v.6 no.4
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    • pp.1-10
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    • 2023
  • Purpose: As an important provision to protect the rights and interests of low-income groups, it is worth studying whether the minimum wage policy can improve the quality of life for people. Research design, data and methodology: Using data from the 2015 and 2017 China General Social Survey (CGSS), this paper employs the logit model to estimate the probability of an individual's annual income being higher than the per capita disposable income of their province. It also utilizes the DID model to analyze the impact of minimum wage increases on individuals' annual incomes. Results: The analysis reveals that an overall increase in the minimum wage raises the probability of an individual's annual income exceeding the per capita disposable income by 3%. Among them, the probability increased by 2.2% for males and by 3.2% for females. Furthermore, the impact of the minimum wage on annual income varies depending on the individual's income level. Notably, the most positive and significant impact is observed for individuals whose income level is close to the minimum wage standard. Conclusions: This provides evidence that the increase in the minimum wage has effectively improved the quality of life for the population.

Predicting typhoons in Korea (국내 태풍 예측)

  • Yang, Heejoong
    • Journal of the Korea Safety Management & Science
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    • v.17 no.1
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    • pp.169-177
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    • 2015
  • We develop a model to predict typhoons in Korea. We collect data for typhoons and classify those depending on the severity level. Following a Bayesian approach, we develop a model that explains the relationship between different levels of typhoons. Through the analysis of the model, we can predict the rate of typhoons, the probability of approaching Korean peninsular, and the probability of striking Korean peninsular. We show that the uncertainty for the occurrence of various types of typhoons reduces dramatically by adaptively updating model parameters as we acquire data.

Tests For and Against a Positive Dependence Restriction in Two-Way Ordered Contingency Tables

  • Oh, Myongsik
    • Journal of the Korean Statistical Society
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    • v.27 no.2
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    • pp.205-220
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    • 1998
  • Dependence concepts for ordered two-way contingency tables have been of considerable interest. We consider a dependence concept which is less restrictive than likelihood ratio dependence and more restrictive than regression dependence. Maximum likelihood estimation of cell probability under this dependence restriction is studied. The likelihood ratio statistics for and against this dependence are proposed and their large sample distributions are derived. A real data is analyzed to illustrate the estimation and testing procedures.

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