59 research outputs found

    Bayesian modeling of clustered competing risks survival times with spatial random effects

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    n some studies, survival data are arranged spatially such as geographical regions. Incorporating spatial associationin these data not only can increase the accuracy and efficiency of the parameter estimation, but it also investigatesthe spatial patterns of survivorship. In this paper, we considered a Bayesian hierarchical survival model in thesetting of competing risks for the spatially clustered HIV/AIDS data. In this model, a Weibull Parametric distributionwith the spatial random effects in the form of county-failure type-level was used. A multivariate intrinsic conditionalautoregressive (MCAR) distribution was employed to model the areal spatial random effects. Comparison amongcompeting models was performed by the deviance information criterion and log pseudo-marginal likelihood. Weillustrated the gains of our model through the simulation studies and application to the HIV/AIDS data

    Measuring the effect of vehicle safety on road traffic crash severity in Iran: using structural equation modeling

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    Objective: Vehicle safety plays a key role in reducing the number of road traffic deaths and serious injuries. This study aims to investigate the effect of vehicle safety on the severity of traffic crashes in Iran using structural equation modeling (SEM). Methods: This was a comparative cross-sectional study of all imported vehicles with Aras free trade zone license plate as well as all domestic vehicles (cars produced in Iran) commuting on Tabriz-Jolfa road. The study population included drivers who had accidents on Tabriz-Jolfa road over a period of one year from September 22, 2020 to September 21, 2021 and were injured or  their vehicles had been damaged (n=652). Data was collected using set of questionnaires with 10 sections. The effect of independent variables, as exogenous latent variables (human, vehicle, and environmental factors), on a dependent variable, as an endogenous latent variable (crash severity) was measured using SEM. All data were analyzed using Mplus 8.0 software. Results: In the structure part of the model with foreign vehicles group, the effect sizes of three exogenous variables, i.e., human, environmental, and vehicle factors, on the dependent variables were found to be 0.412, 0.396 and 0.358, respectively. The effect sizes in the model with domestic vehicles were found to be 0.312, 0.702 and 0.820, respectively. Conclusion: Vehicle factors (variables related to car safety) had a high impact on crash severity in the national license plate and domestically manufactured vehicle group, indicating the necessity of improving vehicle safety

    Effective Management of Energy Internet in Renewable Hybrid Microgrids : A Secured Data Driven Resilient Architecture

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    This paper proposes a two-layer in-depth secured management architecture for the optimal operation of energy internet in hybrid microgrids considering wind turbines, photovoltaics, fuel cell unit, and microturbines. In the physical layer of the proposed architecture, the operation of the grid is formulated as a single objective problem that is solved using teacher learning-based optimization (TLBO). Regarding the cyber layer of the proposed architecture, a two-level intrusion detection system (IDS) is proposed to detect various cyber-attacks (i.e. Sybil attacks, spoofing attacks, false data injection attacks) on wireless-based advanced metering infrastructures. The sequential probability ratio testing (SPRT) approach is utilized in both levels of the proposed IDS to detect cyber-attacks based on a sequence of anomalies rather than only one piece of evidence. The feasibility and performance of the proposed architecture are examined on IEEE 33-bus test system and the results are provided for both islanded and grid-connected operation modes.©2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.fi=vertaisarvioitu|en=peerReviewed

    Spatial analysis of CO and PM10 pollutants in Tehran city

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         Nowadays, air pollution in cities with regard to its harmful outcomes has been turned into one of the serious challenges in urban management. Pollutants as Carbon monoxide, sulfur dioxide, and the aerosols that are known to be among the most important factors related to heart, vascular, and lung disease, have underlined public welfare and health, and the organizations concerned with community health undertake remarkable expenses for disease coming out of these pollutants per year. Awareness of the air situation and its quality over periods and the process of air pollutants’ changes in locations, and especially detection of high risk places can play an important and efficient role in urban health management and land use policy-making. In this paper, for the prediction of the possibility of occurring a pollutant in different locations, based on location information, one modern method of analysis entitled indicator kriging method is introduced. Since, nowadays, CO and PM10 are the two major pollutants in Tehran city, using the mentioned method, the probability of occurrence of each of them in Dey 1390 along with their accuracy is being measured and then a map is provided for the possible occurrence of these pollutants over the whole city of Tehran. 

    Spatial inequalities and predictors of HIV/AIDS mortality risk in Hamadan, Iran: a retrospective cohort study

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    OBJECTIVES Understanding the geographic variation of HIV/AIDS mortality risk and human immunodeficiency virus (HIV) infection could help identify high-burden areas. The aim of our study was to evaluate the effects of predictors of the time interval between HIV diagnosis to death, while accounting for spatial correlations across counties, and to assess patterns of spatial inequalities in the risk of HIV/AIDS mortality in Hamadan Province, Iran. METHODS This retrospective study was conducted on 585 patients. The outcome in this study was the time period between the date of HIV/AIDS diagnosis and the date of death. A Weibull regression model with spatial random effects was used. RESULTS According to multivariate analysis, there were significant associations between age, tuberculosis co-infection, and marital status and the risk of death. In terms of spatial inequalities, a cluster of counties was identified with a somewhat higher death hazard in the north, northwest, northeast, and central regions. Additionally, a cluster with a somewhat lower hazard was identified in the south, southwest, southeast, and west regions. CONCLUSIONS The spatial pattern of HIV/AIDS death risk could reflect inequalities in access to antiretroviral therapy and public health services. Our results underscore the importance of attention to vulnerable groups in urban areas

    Assessing Substances Abuse-Induced Mortality Rates by Autopsy Method in Iran

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    Background: Substance abuse is among the main causes of preventable diseases and premature deaths worldwide. Despite legal efforts to prevent substance abuse, it has increased and imposed significant economic costs on societies. This analytical cross-sectional study aimed to explore the rate of substance abuse-induced mortality in the provinces of Iran, in 2017. We elaborated an evaluation structure to identify nationwide different substance abuse-related mortality rates. Methods: We employed the retrospective data extracted from autopsy, forensic medicine examination, and demographic characteristics from the recordings in the Iranian Legal Medicine Organization (ILMO). Stata and ArcGIS were applied for data analysis. Results: Nationwide, 3089 substance abuse-related deaths were recorded in the ILMO; the incidence rate was 38.17 per million subjects. The deaths mostly occurred in the 30-39 age group and males accounted for 90% of cases. The provinces of Kermanshah, Lorestan, Fars, Hamadan, and Semnan reported significantly higher rates, compared with the provinces of Mazandaran, West-Azerbaijan, and Golestan with the lowest mortality rates per million (74.72, 69.81, 63.42, 61.70, 58.53 vs. 10.82, 12.11, 14.30, respectively). Mortality rates due to the abuse of methadone (20.29), morphine (12.34), amphetamine (5.32), methamphetamine (7.05), codeine (4.21), tramadol (5.96), benzodiazepine (1.47), and diphenoxylate (0.05) were calculated per million populations of Iran.Conclusion: The obtained data suggested that preventive interventions should focus on the 20-40 age group. Methadone, morphine, and methamphetamine were associated with the highest mortality, compared to other substances; thus, they require effective treatment and preventive programs. Iranian Drug Control Headquarters, police department, and policymakers should act more efficiently regarding a preventive strategic plan in this respect

    Environmental factors influencing the distribution of pedestrian traffic accidents in Iran

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    Background: This study aimed to determine the environmental factors affecting the frequency of accidents leading to injury and death related to pedestrians in 31 provinces of Iran. Methods: Data necessary for the study were extracted from databases of traffic police, statistics center, ministry of roads and urban development, and Iran meteorological organization. Hot spots analysis was used based on Getis-Ord G statistics in geographically weighted regression models. Goodness of fit of models was evaluated using the Bayesian information criterion, Akaike's information criterion and Deviance statistics. Results: In this study, 49,409 incidents were investigated. Of these, 48,382 (98) cases were injuries and 1027 (2) cases were fatal accidents. The incidence of fatal accidents does not follow a specific pattern; however, the incidence of accidents leading to injuries is higher in the central and the northeastern provinces of the country and lower in the southern and southeast provinces of the country. The final models showed that the relationship between different variables, including demographic characteristics, road network, and distance from the capital, traffic volume, and rainfall with dependent variables (number of accidents in geographic units), was statistically significant. Conclusion: In order to better design preventive plans for traffic accidents and promote the safety of passageways for pedestrians inside and outside the cities, these factors need to be considered more carefully, and practical solutions should be developed and implemented for their correction

    Households' food expenditures in urban areas of Iran: An application of small area estimation

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    Background: A fundamental factor for human development is food, and inequalities in nutrition have been related to inequalities in health .The purpose of this study was to estimate Household Food Expenditure (HFE) in urban areas of Iran at district-level using small area estimation (SAE) methods.   Design and Methods: We used the Fay-Herriot model, the well-known area-level model of SAE. The main data was urban data of HFE collected by Statistical Centre of Iran at 2013. The environment of our study was urban area of Iran and study unit was household. Results: Findings showed that average number of room at each household, migration rate, proportion of male headed households(PMH) and Proportion of the active population`s employed at district level had a significant effect on HFE. Comparison between aggregated province estimates and estimates reported by SCI was not significant (P=0.609). The lowest and the highest HFE belong respectively to Pishva district with 27,067 thousand rials(TRs) and to Boyer-Ahmad district  with 85,175 TRs. Conclusions: Small-area estimation is advantageous for surveillance of HFE at the district level. This method allows documentation of geographic disparities and improves our understanding of the spatial distribution of HFE in urban areas of Iran

    A system approach on safe emergency evacuation in Subways: A systematic literature review

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    Background: Due to the extensive use of subway transportation in high- and middle-income countries, the safety of passengers has become one of the important challenges in emergency management of subway station. Therefore, the present systematic review aimed to identify environmental and organizational management factors that affect the safe emergency evacuation in subway stations. Materials and Methods: In this systematic literature review, PubMed, Scopus, Web of Science, ProQuest, Google Scholar, Iran Medex, Magiran, and Scientific Information Database from 1990 to 2019 were searched to identify effective emergency management factors in safe emergency evacuation of the subways. A thematic content analysis was employed for data analysis. Results: Of 763 publications retrieved from the searches, 149 studies were included for data analysis. According to the findings, effective environmental and organizational management factors in safe emergency evacuation were discussed in eight subcategories, including infrastructure properties, evacuation-assisting resources, prevention of injuries and mitigation, preparedness for emergency evacuation, emergency response and reconstruction, and maintenance of evacuation facilities. Conclusion: The design of an optimal route for emergency evacuation is the main theme of most studies focusing on environmental factors. While a system approach for designer is needed for effective subway emergency evacuation, human-related factors focusing on injury prevention are also crucial

    Investigation of Relationship between Level of Awareness around Health, Safety and Environment Management System and Its Effects on Safety Climate and Risk Perception by Employees in an Iran Oil Refinery, 2015

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    Special attention of and oil, gas and petrochemical large corporation in the world to the HSE management system is due to its importance in the designing and development of products, services and processes by considering its health, safety and environment requirements. Staff's perception of the existing job risks has a significant impact on their safe behavior at work. This study was conducted to determine the relationship between safety climate and staff's perception of risk with an awareness level among employees of the HSE management system in an oil refinery in Kermanshah. The study population was employees in one of the oil refineries in Iran. After designing and questionnaire psychometric assessment of staff knowledge of HSE management system (Cronbach's alpha was 0.9 and its validity was assessed by certified professionals), Loughborough safety climate questionnaire and Flin risk perception questionnaire were used. Data analysis was performed using SPSS V22 software. Results showed that the relationship between safety climate and awareness level of the HSE management system; also the relationship between safety climate and perception of risk was also getting significant. However, the relationship between perception of risk and awareness level of the HSE management system was not significant. The results of this study showed a moderate awareness of HSE Management System in refinery workers. In this regard, appropriate and proper management policy should be committed to improving the situation. The results of this study is a profile the situation of safety climate in the refinery, which can be used as an indicator for the development of preventive policies and evaluate the performance of the organization's safety and the results of the safety improvement organization
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