Sharif Digital Repository

The use of active modes of travel in school trips has sharply declined for a number of reasons, some of which are rooted in urban design, location of schools, and parental reservations. Thus, policy makers are keen to find practical ways to promote active modes of travel, particularly walking. This study was an effort to determine a tolerable walking distance for school trips and identify factors that made walking trips more reasonable for students. In the vein of understanding the tolerable walking distance, a two-step framework encompassing a random utility method and a hazard-based model was introduced. This framework was applied to a set of data that were collected from middle and high... 

Due to their different sizes and operational characteristics, vehicles other than passenger cars have a different influence on traffic operations especially at intersections. The passenger car equivalent (PCE) is the parameter that shows how many passenger cars must be substituted for a specific heavy vehicle to represent its influence on traffic operation. PCE is commonly estimated using headway-based methods that consider the excess headway utilized by heavy vehicles. In this research, the PCE was estimated based on the delay parameter at three signalized intersections in Tehran, Iran. The data collected were traffic volume, travel time for each movement, signalization, and geometric... 

Many countries use a single water meter for multiple units within a building. This creates a cost externality where the cost of water consumed is spread over all units. Using administrative data from Tehran Water and Wastewater Co. for 2013 and 2014, we find an increase in the number of units on a communal meter on average increases per unit use by 0.4%. Estimation at different levels of units reveals that almost all communal meters have higher per unit water use. The results suggest that removing this externality could save 2.7% water consumption in our sample. © 2018 Elsevier B.V  

Passenger cars (PCs) are a major contributor to urban air pollution, greenhouse gas emissions, and energy security challenges in megacities in developing countries because of their high growth potential. Since the PC fleet changes through time, the projection of air pollutant emissions from PCs is essential for effective emission reduction policymaking. However, the extensive amount of data and proper models are required for this purpose that are not available in many developing countries. Hence, this study develops multiple econometric and emission models and integrate them into a framework to simulate the future stock and activity of PCs and projects PCs’ air pollutants and CO2 emissions... 

Public participation is counted as one of the main indexes in sustainable urban management. Based on their nature, metropolitan cities has several and complex problems. For this purpose Tehran metropolitan area is selected. Quantitative Strategic Planning Matrix (QSPM) weighted through a made-byresearcher questionnaire. The reliability of the model was verified by Cronbach’s alpha coefficient. Evaluation matrix for internal and external factors was equal to 1.944 and 3.413, respectively. The strategies were classified and prioritize by quantitative matrix. Suitable strategies for Tehran city are as follows: developing a strategic plan in field of social control participatory management for... 

The present study was conducted to investigate the impacts of retrofitted CNG vehicles on air pollutant emissions in Tehran over a 20 years period using available statistical data, precise automobile tests, data analysis, and LEAP Software. The obtained results revealed an increase in air pollutant emissions including CO (equal to 1030.77 thousand tons), NOx (equal to 1030.77 thousand tons), THC (269.02 thousand tons) and CO2 (equal to 38.43 thousand tons) resulting from utilizing retrofitted CNG vehicles within the studied period. Considering the obtained results, if the current trend of producing retrofitted CNG vehicles continues, a total cost of 435 million USD will impose on the... 

This paper focuses on low frequency airline service patronage using the data from a survey conducted at Imam Khomeini International Airport in Tehran, Iran. It uses Dominance-based Rough Set Approach (DRSA) for modeling passengers' choices. We compare the method with discrete choice models using a prediction potential measure. Unlike discrete choice methods, it can use qualitative and categorized data without having to transform them into dummy variables. It is found that the prediction accuracy of the proposed technique is better than that of the discrete choice model for the case under consideration  

Nowadays, transportation sector consumes about 27 percent of the whole energy in Iran. Therefore, after domestic and business sectors which consume about 40 percent of the whole energy, transportation is placed in the second rank. However, the financial value of transportation is of the highest importance. Moreover, having 55percent of gasoline product consumption transportation has been also ranked as the largest consumer of gasoline products. Gasoline consumption in transport showed an increase until 1979. During 1980-1981, it decreased slightly and from 1982 have had a permanent upward trend. Oil products consumption in transport sector in 1950 has been less than average 15 million... 

Urban and transportation planners have put a special focus on students' health and fitness in the past decade, however they struggle to find effective policies to promote walking and biking for school trips. Commuting to school is an opportunity to embed a regular physical activity in students' daily routines and prevent many health issues that are stimulated by physical inactivity during childhood. A three level nested logit model is introduced to explain the motives behind school trip modal selection. Four choice situations, namely walking, driving, school busing, and taking public transit are considered. This study, particularly, underscored the significance of model misspecification in... 

Efficient operation of urban water systems necessitates accurate water demand forecasting. We present daily, weekly, and monthly water demand forecasting using dynamic artificial neural network (DAN2), focused time-delay neural network (FTDNN), and K-nearest neighbor (KNN) models for the city of Tehran. The daily model investigates whether partitioning weekdays into weekends and non-weekends can improve forecast results; it did not. The weekly model yielded good results by using the summation of the daily forecast values into their corresponding weeks. The monthly results showed that partitioning the year into high and low seasons can improve forecast accuracy. All three models offer very... 

Over the past few decades, industrial development has caused a dramatic increment in greenhouse gas (GHG) emissions, as a leading cause of climate change. Modifying the industrial plants' environmental performance is the main pillar of improving efficiency that can reduce the waste of resources and make achieving lower-cost global emission reduction targets of the Kyoto protocol's clean development mechanism (CDM) possible. Considering the essentiality of knowledge-based research in increasing the awareness of policymakers by providing better access to accurate and reliable information, an analytical survey on efficiency in oil, gas, and petrochemical industries has been conducted by... 

Purpose: In this study we aimed to develop an optimized prediction model to estimate a fine-resolution grid of ground-level PM2.5 levels over Tehran. Using remote sensing data to obtain fine-resolution grids of particulate levels in highly polluted environments in areas such as Middle East with the abundance of brightly reflecting deserts is challenging. Methods: Different prediction models implementing 3 km AOD products from the MODIS collection 6 and various effective parameters were used to obtain a reliable model to estimate ground-level PM2.5 concentrations. In this regards, the linear mixed effect model (LME), multi-variable linear regression model (MLR), Gaussian process model (GPM),... 

Thermal stratification accompanied by a release of nutrients from sediment is a serious problem for the management of water quality. Water aeration and mixing technology can be widely used to control endogenous pollution and algae growth in reservoirs and lakes by water quality managers. In this research, a diffuser aeration system, was installed in a water column, in the Mamloo stratified Reservoir; and the impact of artificial aeration was brought under extensive assessment in relevance with the qualitative and biological parameters of the water, during the preliminary 6 d of aeration. The results showed that the thermal stratification was remarkably disturbed. After aeration, the amount... 

This paper examines the role of transportation demand management (TDM) policies on commuters' mode choice in the city of Tehran. The analysis is based on the results of a stated preferences survey developed through the design of experiments approach. Five policies covering increasing parking cost, increasing fuel cost, cordon pricing, transit time reduction, and transit access improvement are assessed in order to study their impact on commuters' consideration of six modes of transportation to travel to work. A multinomial logit model was developed for the 366 commuters who regularly commute to their workplace in the center of the city. In addition to a number of commuting and contextual... 

Karyotyping, is the process of classification of human chromosomes within the microscopic images. This is a common task for diagnosing many genetic disorders and abnormalities. Automatic Karyotyping algorithms usually suffer the poor quality of the images due to the non rigid nature of the chromosomes which makes them to have unpredictable shapes and sizes in various images. One of the main problems that usually need operator's interaction is the identification and separation of the overlapping/touching chromosomes. This paper presents an effective algorithm for identification of any cluster of the overlapping/touching chromosomes together with the number of chromosomes in the cluster, which... 

Research in the choice behavior of air travelers has evolved to include an analytical focus on variation in the sensitivities of travelers to factors influencing itinerary choice. Some choice studies have moved beyond a focus on assumed representative, mean-level sensitivities toward a goal of representing the distribution of preferences across a sample. The mixed multinomial logit model has served as a valuable means of estimating such distributions of air travel preferences, including studies of business travelers, impacts of airport level-of-service attributes, distributions of willingness-to-pay (WTP), and information-processing strategies. Does the insight gained in previous studies,... 

Development of technology has made possible the invention of innovative and modern methods to partially solve the problems caused by traffic congestion through decreasing the need for physical transportation; one such method being telecommuting. Although, research has been conducted to model employees' and employers' attitude towards telecommuting at micro levels, few predictions have been reported regarding its aggregate demand at the macro level of a city, generally because of the complexity and multi-dimensionality of the subject. In this paper, an approach for the estimation of potential aggregate telecommuting demand is proposed to partly fill the gap in the literature; and applied for... 

Noise pollution in urban areas has many harmful effects on the citizens. There are varieties of noise generation sources of which the traffic noise could be a major source. The point which is perhaps less noticed is that sound level is not the only parameter to indicate the extent and intensity of noise pollution. Situation of urban land uses, distribution of population centers and types of passages can deeply affect the concern on this environmental issue but not with a similar ratio. This article presents an overlaying technique to define noise prone areas using all different factors involved. A case study was carried out in the District 14 of Tehran Metropolitan City where there are busy... 

The effect of Solid State Fermentation (SSF) on Chitosan production by A. niger was investigated. A. niger BBRC 20004 from Biochemical and Bioenvironmental Research Centre of Sharif University of Technology (Tehran, Iran), was grown on corn residue. Chitosan was extracted from the fungal mycelia using hot alkaline and acid treatment. A. niger was incubated for 12 days on corn residue with moisture content of 35 % and 1.12 % of nitrogen. The Chitosan was obtained and 10.9 g/kg of Urea dry residue was added in various amounts to the medium in order to evaluate the effect of the nitrogen concentration in the production of Chitosan. The highest amount of Chitosan obtained by 6.5 g of urea after... 

Noise is one of the most important sources of pollution in the metropolitan areas. The recognition of road traffic noise as one of the main sources of environmental pollution has led to develop models that enable us to predict noise level from fundamental variables. Traffic noise prediction models are required as aids in the design of roads and sometimes in the assessment of existing, or envisaged changes in, traffic noise conditions. The purpose of this study was to design a prediction road traffic noise model from traffic variables and conditions of transportation in Iran. This paper is the result of a research conducted in the city of Hamadan with the ultimate objective of setting up a...