• Title/Summary/Keyword: random factor

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Peak Factors for Bridges Subjected to Asynchronous Multiple Earthquake Support Excitations

  • Yoon, Chong-Yul;Park, Joon-Seok
    • Journal of the Korean Society of Hazard Mitigation
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    • v.11 no.1
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    • pp.7-13
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    • 2011
  • Accurate response analysis of long span bridges subjected to seismic excitation is important for earthquake hazard mitigation. In this paper, the performance of a typical four span continuous reinforced concrete bridge model subjected to asynchronous multiple seismic excitations at the supports is investigated in both the time and frequency domains and the results are compared with that from a relevant uniform support excitations. In the time domain analysis, a linear modal superposition approach is used to compute the peak response values. In the frequency domain analysis, linear random vibration theory is used to determine the root mean square response values where the cross correlation effects between the modal and the support excitations on the seismic response of the bridge model are included. From the two sets of results, a practical range of peak factors which are defined to be the ratio of peak and the root mean square responses are suggested for displacements and forces in members. With reliable practical values of peak factors, the frequency domain analysis is preferred for the performance based design of bridges because of the computational advantage and the generality of the results as the time domain analysis only yields results for the specific excitation input.

Factors Affecting Breast Self-examination Behavior Among Female Healthcare Workers in Iran: The Role of Social Support Theory

  • Bashirian, Saeed;Barati, Majid;Shoar, Leila Moaddab;Mohammadi, Younes;Dogonchi, Mitra
    • Journal of Preventive Medicine and Public Health
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    • v.52 no.4
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    • pp.224-233
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    • 2019
  • Objectives: In women, breast cancer is the most common cancer and the leading cause of cancer death. Screening tests are the basis for early diagnosis. In Iranian women, the mortality rate of breast cancer is high due to insufficient screening examinations and delayed visits for care. Therefore, this study aimed to determine the factors affecting breast self-examinations among Iranian women employed in medical careers. Methods: This cross-sectional study included 501 women working in the medical professions at Hamadan University of Medical Sciences in western Iran in 2018. The subjects were selected by stratified random sampling. Data were collected using a researcher-developed, self-report questionnaire that contained demographic information and questions based on protection motivation theory and social support theory. Descriptive data analysis was conducted using SPSS version 23 and model fitting with PLS version 2. Results: The mean age of the participants was $37.1{\pm}8.3years$, and most of the women (80.4%) were married. Most women had a bachelor's degree (67.5%). The findings of this study showed that the coping appraisal construct was a predictor of protection motivation (${\beta}=0.380$, p<0.05), and protection motivation (${\beta}=0.604$, p<0.05) was a predictor of breast self-examination behavior. Additionally, social support theory (${\beta}=0.202$, p<0.05) had a significant positive effect on breast self-examination behavior. Conclusions: The frequency of practicing self-examinations among women employees in the medical sector was low; considering the influence of social support as a factor promoting screening, it is necessary to pay attention to influential people in women's lives when designing educational interventions.

The Impact of Transactional Leadership to Organizational Commitment: The Mediating Effect of Followership (거래적 리더십이 조직몰입에 미치는 영향: 팔로워십의 매개효과)

  • Kang, Choon-Su;Lee, Young Gyun
    • Journal of Digital Convergence
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    • v.16 no.11
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    • pp.81-87
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    • 2018
  • Transactional leadership(TL) is to provide constructive feedback to organizational employee's commitment and to engender a positive impact on individuals and organizations. In this respect, this study is to investigate police's TL could positively influence organizational commitment, and is there a mediated effect in this impact empirically. This study based on the analysis on a random sample of police who has worked in Seongnam, Kwangjoo, and Hanam cities. The findings are the follows. (1) Police's TL has a positive effect on followership. (2) Police's TL has a positive effect on employees' commitment highly. (3) Police's followership has a positive effect on employees' commitment highly. (4) Followership has a partial mediated effect to relationship between Police's TL and employees' commitment. In these results, transactional leadership and followership are to verify a critical factor to improve police's organizational commitment.

Development of a novel fatigue damage model for Gaussian wide band stress responses using numerical approximation methods

  • Jun, Seock-Hee;Park, Jun-Bum
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.12 no.1
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    • pp.755-767
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    • 2020
  • A significant development has been made on a new fatigue damage model applicable to Gaussian wide band stress response spectra using numerical approximation methods such as data processing, time simulation, and regression analysis. So far, most of the alternative approximate models provide slightly underestimated or overestimated damage results compared with the rain-flow counting distribution. A more reliable approximate model that can minimize the damage differences between exact and approximate solutions is required for the practical design of ships and offshore structures. The present paper provides a detailed description of the development process of a new fatigue damage model. Based on the principle of the Gaussian wide band model, this study aims to develop the best approximate fatigue damage model. To obtain highly accurate damage distributions, this study deals with some prominent research findings, i.e., the moment of rain-flow range distribution MRR(n), the special bandwidth parameter μk, the empirical closed form model consisting of four probability density functions, and the correction factor QC. Sequential prerequisite data processes, such as creation of various stress spectra, extraction of stress time history, and the rain-flow counting stress process, are conducted so that these research findings provide much better results. Through comparison studies, the proposed model shows more reliable and accurate damage distributions, very close to those of the rain-flow counting solution. Several significant achievements and findings obtained from this study are suggested. Further work is needed to apply the new developed model to crack growth prediction under a random stress process in view of the engineering critical assessment of offshore structures. The present developed formulation and procedure also need to be extended to non-Gaussian wide band processes.

Optimization of the whole extract of Zarawand Mudaharaj (Aristolochia rotunda L.) root by Response Surface Methodology (RSM)

  • Ansari, MD Zakir;Sofi, Ghulamuddin;Hamiduddin, Hamiduddin;Ahmad, Haqeeq;Basri, Rabia;Alam, Abrar
    • CELLMED
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    • v.11 no.3
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    • pp.15.1-15.9
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    • 2021
  • The chemical constitution of a drug has been accepted as an important basis for pharmacological action in Unani medicine. Various dosage forms have been developed on this concept, such as decoctions (Joshanda), infusions (Khesanda), extract (Rub / Usara), and syrup. Zarawand Mudaharaj (ZM.) / Aristolochia rotunda L. root was subjected to extraction process using Soxhlet's apparatus by using Response Surface Methodology (RSM) to design the number of random runs of the extracts with variation in the factors of temperature, the concentration of ethanol in water, time for extraction, for optimizing and maximizing the yield concentration. The data obtained, was analyzed with regression equation and ANOVA two-way summary to interpret the interaction of the factors for yield maximization. Minitab version 18 was used to design and analyze data. Validation of the optimum conditions for maximum yield of the whole extract of ZM. Root was carried out by re-run of the extract using the optimized conditions. The maximum yield percentage thus obtained using RSM was 20.87% whereas using these optimum conditions 21.35 % yield was obtained thereby validating the method. The association between the response functions and the process variables was identified by a three-factor recorded Box-Behnken design. In the present study RSM is used because itis a cheap and affordable method to optimize maximum yield percentage which may be reliably used by researchers. The study set in the surface conditions for ZM. root extraction by the Soxhlet apparatus for maximizing the yield percentage.

A Structural Relationship among Informational Leadership, Self-efficacy, Communication Ability, and Job Satisfaction of Secondary School Teachers

  • Yu, Pyeong-su
    • Journal of the Korea Society of Computer and Information
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    • v.27 no.4
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    • pp.205-212
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    • 2022
  • The purpose of this study was to analyze the structural relationship between the informational leadership, self-efficacy, communication ability, and job satisfaction of secondary school teachers. In order to achieve the purpose of this study, the following research questions were set up. First, what is the structural relationship between teachers' information leadership, self-efficacy, communication ability, and job satisfaction? Second, what is the mediating effect of self-efficacy and communication ability in the influence of teachers' informational leadership on job satisfaction? J-Do's secondary school was sampled through random sampling from the population. A total of 600 subjects were sampled. The results of this study show that for secondary school teachers, self-efficacy and communication skills play an important role as a motivating factor for job satisfaction. To have teachers' self-efficacy and communication skills, teachers' respect for opinions and participation in decision-making on school management It should be developed in the direction of expanding and creating a cooperative organizational climate. In addition, it was found that it was necessary to change individual teachers' efforts or perceptions in consideration of individual characteristics and environmental characteristics.

Ethnic Variation and Its Association With Malaria Awareness: A Cross-sectional Study in East Nusa Tenggara Province, Indonesia

  • Guntur, Robertus Dole;Kingsley, Jonathan;Islam, Fakir M. Amirul
    • Journal of Preventive Medicine and Public Health
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    • v.55 no.1
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    • pp.68-79
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    • 2022
  • Objectives: This study investigated associations between ethnicity and malaria awareness in East Nusa Tenggara Province (ENTP), Indonesia. Methods: A community-based cross-sectional study was conducted upon 1503 adults recruited by multi-stage cluster random sampling. A malaria awareness questionnaire was used to collect data, according to which participants were classified as aware or unaware of malaria. Logistic regression was applied to quantify the strength of associations of factors with malaria awareness. Results: The participation rate in this study was high (99.5%). The participants were distributed relatively evenly among the Manggarai, Atoni, and Sumba ethnicities (33.0, 32.3, and 30.2%, respectively). Malaria awareness was significantly different amongst these groups; it was most common in the Manggarai ethnicity (65.1%; 95% confidence interval [CI], 59.9 to 70.3) and least common in the Sumba ethnicity (35.0%; 95% CI, 27.6 to 42.4). The most prominent factor influencing the malaria awareness in the Sumba and Manggarai ethnicities was education level, whilst it was socioeconomic status (SES) in the Atoni ethnicity. The likelihood of malaria awareness was significantly higher in adults with an education level of diploma or above (adjusted odds ratio [aOR], 21.4; 95% CI, 3.59 to 127.7 for Manggarai; aOR, 6.94; 95% CI, 1.81 to 26.6 for Sumba). Malaria awareness was significantly more common amongst high-SES adults in the Atoni group (aOR, 24.48; 95% CI, 8.79 to 68.21). Conclusions: Low education levels and low SES were prominent contributors to lower levels of malaria awareness in rural ENTP. Interventions should focus on improving malaria awareness to these groups to support the Indonesian government's national commitment to achieve a malaria elimination zone by 2030.

Moment-rotational analysis of soil during mining induced ground movements by hybrid machine learning assisted quantification models of ELM-SVM

  • Dai, Bibo;Xu, Zhijun;Zeng, Jie;Zandi, Yousef;Rahimi, Abouzar;Pourkhorshidi, Sara;Khadimallah, Mohamed Amine;Zhao, Xingdong;El-Arab, Islam Ezz
    • Steel and Composite Structures
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    • v.41 no.6
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    • pp.831-850
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    • 2021
  • Surface subsidence caused by mining subsidence has an impact on neighboring structures and utilities. In other words, subsurface voids created by mining or tunneling activities induce soil movement, exposing buildings to physical and/or functional destruction. Soil-structure is evaluated employing probability distribution laws to account for their uncertainty and complexity to estimate structural vulnerability. In this study, to investigate the displacement field and surface settlement profile caused by mining subsidence, on the basis of a Winklersoil model, analytical equations for the moment-rotation response ofsoil during mining induced ground movements are developed. To define the full static moment-rotation response, an equation for the uplift-yield state is constructed and integrated with equations for the uplift- and yield-only conditions. The constructed model's findings reveal that the inverse of the factor of safety (x) has a considerable influence on the moment-rotation curve. The maximal moment-rotation response of the footing is defined by X = 0:6. Despite the use of Winkler model, the computed moment-rotation response results derived from the literature were analyzed through the ELM-SVM hybrid of Extreme Learning Machine (ELM) and Support Vector Machine (SVM). Also, Monte Carlo simulations are used to apply continuous random parameters to assess the transmission of ground motions to structures. Following the findings of RMSE and R2, the results show that the choice of probabilistic laws of input parameters has a substantial impact on the outcome of analysis performed.

Non-Gaussian wind features over complex terrain under atmospheric turbulent boundary layers: A case study

  • Hongtao, Shen;Weicheng, Hu;Qingshan, Yang;Fucheng, Yang;Kunpeng, Guo;Tong, Zhou;Guowei, Qian;Qinggen, Xu;Ziting, Yuan
    • Wind and Structures
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    • v.35 no.6
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    • pp.419-430
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    • 2022
  • In wind-resistant designs, wind velocity is assumed to be a Gaussian process; however, local complex topography may result in strong non-Gaussian wind features. This study investigates the non-Gaussian wind features over complex terrain under atmospheric turbulent boundary layers by the large eddy simulation (LES) model, and the turbulent inlet of LES is generated by the consistent discretizing random flow generation (CDRFG) method. The performance of LES is validated by two different complex terrains in Changsha and Mianyang, China, and the results are compared with wind tunnel tests and onsite measurements, respectively. Furthermore, the non-Gaussian parameters, such as skewness, kurtosis, probability curves, and gust factors, are analyzed in-depth. The results show that the LES method is in good agreement with both mean and turbulent wind fields from wind tunnel tests and onsite measurements. Wind fields in complex terrain mostly exhibit a left-skewed Gaussian process, and it changes from a softening Gaussian process to a hardening Gaussian process as the height increases. A reduction in the gust factors of about 2.0%-15.0% can be found by taking into account the non-Gaussian features, except for a 4.4% increase near the ground in steep terrain. This study can provide a reference for the assessment of extreme wind loads on structures in complex terrain.

Association Between the Prevalence of Schistosomiasis in Elementary School Students and Their Parental Occupation in Sudan

  • Jin, Yan;Cha, Seungman;Kim, Youngjin;Hamdan, Hamdan Mustafa;Elhag, Mousab Siddig;Ismail, Hassan Ahmed Hassan Ahmed;Lee, Keon Hoon;Hong, Sung-Tae
    • Parasites, Hosts and Diseases
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    • v.60 no.1
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    • pp.51-56
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    • 2022
  • Global efforts to identify groups at high risk for schistosomiasis have mainly concentrated on identifying their geographical distribution. Investigations on the socioeconomic characteristics of high-risk groups are relatively scarce. This study aimed to explore the associations between schistosomiasis among students and their parents' occupations. A nationwide cross-sectional survey was conducted targeting 105,167 students in 1,772 primary schools across Sudan in 2017. From these students, 100,726 urine and 96,634 stool samples were collected to test for Schistosoma haematobium and S. mansoni infection. A multi-level mixed effect analysis was used with age and sex as fixed factors, and school as a random factor. The odd ratios (ORs) of practicing open defecation among farmers' children were almost 5 times higher than their counterparts whose parents were government officials (OR=4.97, 95% confidence intervals (CIs): 4.57-5.42, P<0.001). The ORs of contacting water bodies for watering livestock among farmers' children were more than 4 times higher than those of children whose parents were government officials (OR=4.59, 95% CIs: 4.02-5.24, P<0.001). This study shows that schistosomiasis represents a disease of poverty and that farmers' children constituted a high-risk group.