72 research outputs found
Accuracy assessment of Digital Surface Models generated by Semiglobal matching algorithm using Lidar data
To measure the accuracy of Digital Surface Models (DSMs) generated by high resolution satellite images (HRSI) using semi-global matching algorithm in comparison with LIDAR DSMs, two different test areas with different properties and corresponding attributes and magnitudes of errors are considered. Error characteristics are classified as systematic and gross errors and significance of them to measure the accuracy of DSMs are evaluated. In this manner and to avoid the influence of outliers in accuracy assessment robust statistical methods are proposed. According to final values obtained for two test areas it can be concluded that the performance of DSMs generated by stereo matching for mountainous wooden areas in respect to the accuracy of LIDAR DSM are poor. In contrast, in case of residential urban areas the quality of the DSM generated by HRSI is able to follow the accuracy of LIDAR data
Rail Track Detection and Projection-Based 3D Modeling from UAV Point Cloud
The expansion of the railway industry has increased the demand for the three-dimensional modeling of railway tracks. Due to the increasing development of UAV technology and its application advantages, in this research, the detection and 3D modeling of rail tracks are investigated using dense point clouds obtained from UAV images. Accordingly, a projection-based approach based on the overall direction of the rail track is proposed in order to generate a 3D model of the railway. In order to extract the railway lines, the height jump of points is evaluated in the neighborhood to select the candidate points of rail tracks. Then, using the RANSAC algorithm, line fitting on these candidate points is performed, and the final points related to the rail are identified. In the next step, the pre-specified rail piece model is fitted to the rail points through a projection-based process, and the orientation parameters of the model are determined. These parameters are later improved by fitting the Fourier curve, and finally a continuous 3D model for all of the rail tracks is created. The geometric distance of the final model from rail points is calculated in order to evaluate the modeling accuracy. Moreover, the performance of the proposed method is compared with another approach. A median distance of about 3 cm between the produced model and corresponding point cloud proves the high quality of the proposed 3D modeling algorithm in this study
Selecting the best architectural form of the office building with the level of non-stop function against explosion
Regarding the importance of structures in sustainable development of countries, the necessity to consider them versus inflicted forces has an especial position. One of the inflicted forces upon these structures is explosion. Given that the resistance of a construction against blast wave depends on the form and shape of the building, numbers of trap doors and openings, power and quality of materials utilized in the building; in consequence, studying and evaluating types of construction forms versus outcomes resulted from explosion find importance. The behavior of three kinds of buildings including the forms of cone, hemisphere and frustum were, therefore, evaluated in the research. Various methods can be applied in order to assess behavior of construction against blast load, however, Finite Element method has been utilized in the article duo to particular capabilities of it in the blast assessments. Then, results of blast loading over the constructions were surveyed and it was concluded that buildings with hemispherical form show the best manner and providing openings called colloquially blast walls are used in the building; construction resistance versus blast load is raised
Photocatalytic Removal of Methylbenzene Vapors by MnO2/Al2O3/Fe2O3 Nano composite
Methyl benzene, which has carcinogenic effects, is a volatile organic compound that is widely used in various industries. Nano composites of Mno2/Al203/Fe203, which is a new photocatalyst, have not been applied to remove contaminants from air streams. Therefore, the aim of the present study was to investigate the photocatalytic removal of ethyl benzene by using this nano composite activated by visible light. Morphological characteristics of the synthesized Nano composite in a sol-gel method are determined through XRD, FTIR, and SEM. Through the photocatalyst process and by the use of visible light radiation, the synthesized Nano composite is used to degrade ethyl benzene in the gas phase. In order to estimate the main effects and interaction ones and to optimize the experiment numbers, the response surface method was used. Operational parameters investigated in the study are the initial concentration of contaminants, relative humidity, and the residence time, which were considered in three levels; further, the experiments were designed by Design Expert version 9 software. The results show the Nano composite particle sizes were less than 82 nanometers. The findings also indicate that relative humidity and residence time were effective parameters in removal efficiency of ethyl benzene. This Nano composite, at the optimal conditions, was capable of removing 98.72% of the pollutants, with an initial content of 300 ppm. MnO2/Al2O3/Fe2O3 Nano composite is a suitable catalyst to remove ethyl benzene from air streams. Among the features of the Nano composite are reaction at room temperature and lower production dangerous byproducts, which are the main advantages of this Nano composite as compared with other nano composites
Photocatalytic Removal of Methylbenzene Vapors by MnO2/Al2O3/Fe2O3 Nano composite
Methyl benzene, which has carcinogenic effects, is a volatile organic compound that is widely used in various industries. Nano composites of Mno2/Al203/Fe203, which is a new photocatalyst, have not been applied to remove contaminants from air streams. Therefore, the aim of the present study was to investigate the photocatalytic removal of ethyl benzene by using this nano composite activated by visible light. Morphological characteristics of the synthesized Nano composite in a sol-gel method are determined through XRD, FTIR, and SEM. Through the photocatalyst process and by the use of visible light radiation, the synthesized Nano composite is used to degrade ethyl benzene in the gas phase. In order to estimate the main effects and interaction ones and to optimize the experiment numbers, the response surface method was used. Operational parameters investigated in the study are the initial concentration of contaminants, relative humidity, and the residence time, which were considered in three levels; further, the experiments were designed by Design Expert version 9 software. The results show the Nano composite particle sizes were less than 82 nanometers. The findings also indicate that relative humidity and residence time were effective parameters in removal efficiency of ethyl benzene. This Nano composite, at the optimal conditions, was capable of removing 98.72% of the pollutants, with an initial content of 300 ppm. MnO2/Al2O3/Fe2O3 Nano composite is a suitable catalyst to remove ethyl benzene from air streams. Among the features of the Nano composite are reaction at room temperature and lower production dangerous byproducts, which are the main advantages of this Nano composite as compared with other nano composites
A Data-Driven Statistical Approach for Monitoring and Analysis of Large Industrial Processes
Monitoring and fault detection of industrial processes is an important area of research in data science, helping effective management of the plant by the remote operator. In this article, a data-driven statistical model of a process is estimated using the principal component analysis (PCA) method and the associated probability density function. The aim is to use the model to monitor and detect the incurred faults in the industrial plant. The experimental data are collected by finding the suitable subsystems of a Recycle Gas in Ethylene Oxide production process, and a subset of nine variables are extracted for further statistical analysis of the system. The performance of the developed model for monitoring purpose is evaluated by using faulty and close to faulty inputs as the new test data
Mapping Groundwater Resource using Multispectral Sentinel 2 and Fuzzy Logic method, Case Study: Salafchegan, Qom, Iran
Groundwater is one of the essential freshwater sources for human consumption, with the highest reserves of fresh water on earth after glaciers and glaciers. Conservation and maintenance of groundwater quality in a large area require an overview of the status and potential of groundwater resources in that area, which can be applied to potential areas using remote sensing technology. In this study, after extracting the factors influencing the formation of groundwater aquifers from the Sentinel satellite image, appropriate information layers were prepared and integrated into the ArcGIS using different fuzzy operators and potential maps prepared with the location of groundwater wells. The area was validated. The results of combining slope layers, slope direction, lithology, drainage length density, lineament length density, lineament buffer, drainage buffer, and vegetation in the area showed that fuzzy multiplication and gamma operators could be used as suitable operators for Introducing information layers to identify groundwater potential in the area. Also, using the gamma numbers 0.1 gave better results than larger gamma numbers. The research results showed that 15.9% of the studied area has good and very good potential for the presence of underground water in the production map using the fuzzy gamma with gamma 0.1 method. Also, this map was validated by 70.1% of water wells in the region. The normalized ratio of accuracy to validity in the final production model with this method was estimated to be 54%, which is entirely acceptable compared to other methods
The Translation and Psychometric Evaluation of the Persian Version of Iowa Tinnitus Primary Function Questionnaire
Background and Aim: Tinnitus is a common symptom and affects patients differently. The Iowa Tinnitus Primary Function (ITPF) questionnaire evaluates tinnitus in four areas: concentration, emotion, hearing, and sleep. This study aimed to translate and then assess the psychometrics of the ITPF questionnaire.
Methods: This is a cross-sectional and methodological (test construction) study. The questionnaire was translated by the Word Health Organization protocol. The validity and reliability of the questionnaire were assessed. The measured validities were the content, face, and discriminative. The reliability was estimated by internal consistency and test-retest stability. We also measured the effects of age and sex on the questionnaire’s score.
Results: The questionnaire was translated based on the protocol. Each item of the questionnaire was understandable for patients and healthy participants. The face and content validities were confirmed by the patients and specialists, respectively. The score of 10.97 was determined as the cutoff point between patients and healthy participants, with a sensitivity of 86.70% and a specificity of 96.10%. The Cronbach α was found to be 0.958, and the intraclass correlation coefficient was 0.975. No significant effect was observed for age (p=0.314) and gender (p=0.866).
Conclusion: The Persian version of the questionnaire showed high validity and reliability. It could be used in research and clinical settings
Photocatalytic Removal of Methylbenzene Vapors by MnO2/Al2O3/Fe2O3 Nano composite
Methyl benzene, which has carcinogenic effects, is a volatile organic compound that is widely used in various industries. Nano composites of Mno2/Al203/Fe203, which is a new photocatalyst, have not been applied to remove contaminants from air streams. Therefore, the aim of the present study was to investigate the photocatalytic removal of ethyl benzene by using this nano composite activated by visible light. Morphological characteristics of the synthesized Nano composite in a sol-gel method are determined through XRD, FTIR, and SEM. Through the photocatalyst process and by the use of visible light radiation, the synthesized Nano composite is used to degrade ethyl benzene in the gas phase. In order to estimate the main effects and interaction ones and to optimize the experiment numbers, the response surface method was used. Operational parameters investigated in the study are the initial concentration of contaminants, relative humidity, and the residence time, which were considered in three levels; further, the experiments were designed by Design Expert version 9 software. The results show the Nano composite particle sizes were less than 82 nanometers. The findings also indicate that relative humidity and residence time were effective parameters in removal efficiency of ethyl benzene. This Nano composite, at the optimal conditions, was capable of removing 98.72% of the pollutants, with an initial content of 300 ppm. MnO2/Al2O3/Fe2O3 Nano composite is a suitable catalyst to remove ethyl benzene from air streams. Among the features of the Nano composite are reaction at room temperature and lower production dangerous byproducts, which are the main advantages of this Nano composite as compared with other nano composites
Developing a new hybrid MCDM method for selection of the optimal alternative of mechanical longitudinal ventilation of tunnel pollutants during automobile accidents
Breathable air inside the tunnel is an undeniable necessity and beside natural ventilation, the tunnel should be reliably organized, to automatically provide healthy air under different conditions. Among methods of tunnel ventilation, longitudinal and transverse modes are the most common mechanical methods. This research is focused on selection of the optimal method for mechanical longitudinal ventilation of tunnel pollutants from four presented models. In terms of this research, the authors used SWARA (Step-wise Weight Assessment Ratio Analysis) as one of the most versatile MCDM (Multiple-Criteria Decision-Making) methods for managerial decision making in complex situations with multiple and varied measures. Fourteen experts of different fields were involved. The research model was established based on expert ideas and the following criteria: smoke control (CÂ 1), safety level (CÂ 2), design complexity (CÂ 3), investment costs (C4), increasing concentration of pollutants until portal (C5), smoke laden section (C6) and simultaneous evacuation and fire fighting (C7). SWARA method was applied to evaluate criteria while VIKOR (VlseKriterijumska Optimizacija I Kompromisno Resenje) method was used to evaluate and rank four alternatives of this research, namely: 1) jet fans with spot extraction by axial fans (A1); 2) axial fans with Saccardo nozzle (AÂ 2); 3) jet fans with shaft axial fans (AÂ 3); 4) jet fans only (AÂ 4). Final results illustrate that jet fans with spot extraction by axial fans is the best choice. Finally, the authors believe that this new hybrid model of MCDM methods can be useful as a new framework in different fields of research
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