Sharif Digital Repository

The spatiotemporal dynamic of salinity concentration (SC) in saline lakes is strongly dependent on the rate of water flow into the lake, water circulation, wind speed, evaporation rate, and the phenomenon of salt precipitation and dissolution. Although in-situ observations most reliably quantify water quality metrics, the spatiotemporal distribution of such data are typically limited and cannot be readily extrapolated for either long-term projections or extensive area. Alternatively, remotely sensed imagery has facilitated less expensive and a stronger ability to estimate water quality over a wide range of spatiotemporal resolutions. This study introduces an adaptive learning model that... 

The water level of Lake Urmia has experienced a drop of 7.83 meters, from 1995 to 2017. According to previous studies, the uncontrolled development of agriculture, high consumption cultivation pattern, overuse of water resources for agricultural use and high water loss due to low irrigation efficiency, are the most important factors in the drying of Lake Urmia. Since agricultural sector is the largest water consumer (approximately 90%), the Lake Urmia Restoration Program has decided to study and implement the 40% reduction of water consumption in agricultural sector plans.Due to the inherent complexity of the Urmia Lake basin, accurate and realistic evaluation of the effectiveness of the... 

Water shortage, population growth, and high levels of urban water demand are among main challenges of water demand management for developing countries and cities, and also for megacities. Urban water management systems, as they are complex adaptive systems, complex interactions exist among elements affecting the system. In other words, action from a subpart can trigger other parts, and also the whole system to respond in reaction. In this study, socio-economic water consumption behavior of households is studies and simulated in an agent-based modeling platform. First, households are interviewed and, using the qualitative data extracted from interviews and also the behavioral science... 

GB and Miankale Wetland are one of the most valuable water areas in the country from an ecological perspective, providing a habitat for a wide range of aquatic species and birds as well as providing a platform for fishing and tourism for locals. Recently, this wildlife refuge has experienced a crisis of reduced water levels and degraded water quality. Past studies have examined how fluctuations in the Caspian Sea water level affect GB's water quantity and quality. Due to the critical situation of Gorgan Bay, other factors affecting its water balance and upstream basin need to be examined, such as ground water flow and consumption, precipitation, and evaporation, and how they all affect the... 

StorAge selection (SAS) functions describe the mechanism by which water particles with different ages exit a hydrological system through outfluxes such as streamflow and evapotranspiration (ET). The shape of the ET SAS functions affects the storage residence time distributions, ET travel time distributions, and discharge travel time distributions that control the hydrochemical dynamics of water. They also carry fundamental information to understand the response behavior of the system, and are affected by processes such as precipitation, outflow, ET, as well as the physical properties of the system. To better understand the shape of these functions, other important factors such as the type... 

This study aimed to investigate the efficiency of machine learning algorithms in capturing the dynamics of water particles' age distribution and in estimating the time series of median travel time (MTT) in river basins. The mechanism of solute transport in a catchment does not follow the hydrograph shape of the catchment and depends on the spatial and temporal distribution of solute resident time. The equations governing the age dynamics of water particles discharged from a catchment have been presented analytically in recent research. These equations showed that the transfer of solutes depends on various factors, including climatic conditions, basin topography, and basin vegetation. Also,... 

The purpose of this study is to introduce a new indicator to estimate the amount of irrigation water in excess of the need and also to determine the optimal irrigation pattern to reduce water loss in agriculture. According to the Food and Agriculture Organization of the United Nations, the major loss of fresh water takes place in agriculture, and the reduction of water resources is more significant in developing countries that do not have advanced agricultural equipment. One of the challenges in the studies related to reducing the amount of water used in agriculture is a lack of knowledge on the spatial distribution and temporal changes in water loss in a region. Although estimation of... 

Many of Iran's wetlands are going dry because of the expansion of anthropogenic activities like the exorbitant withdrawal of groundwater resources and excessive use of water for agricultural purposes. Bakhtegan, Hoor-ol-azim, Anzali, and Miankaleh are some of the most notable examples of this issue in the past two decades. The crucial role of wetlands in preserving the biodiversity of flora and fauna and supplying groundwater resources necessitates continuous monitoring of the quantitative and qualitative changes in the surface water of wetlands. The main focus of this research is quantifying the reduction in wetlands' surface water using K-means and random forest algorithms based on... 

The unavoidable consequences of increased demand for, and decreased supply of, various natural resources, especially water, have caused increased conflict over their allocation. Water allocations merely based on a water rights approach usually do not make efficient use of water for the whole river basin. Thus, there is a need for a comprehensive and stable allocation method that can satisfy all the involved interest groups. One of these methods is game theory that can be used to allocate water resources among riparian parties regarding principles of equity, efficiency and sustainability. In this study, a comprehensive linear programming model has been developed firstly to achieve the optimal... 

Annular combustion chambers used in small turbine motors which incorporate centrifugal (rotary) injectors for injecting fuel, are known as Slinger combustion chambers. The Slinger injector works in such a way that fuel enters from an inner tube in motor shaft and exits with high pressure from the holes on the cylinder connected to the shaft. Because of the high centrifugal force, the fuel is sprayed with high quality after entering the combustion chamber. Type and angle of spray, fuel-air mixing type, combustion phenomena and flame stability makes this different than other annular combustion chambers. The process of combustion in the Slinger chamber of YJ402 motor is numerically simulated in... 

Trip demand analysis is among the most important parts in comprehensive transportation studies. Developing four stage models including trip generation, trip distribution, mode choice, and assignment are so common in demand analyzing. In this study, trip generation models have been studied and to analyze data, two different methods including OLR and GWR are utilized. This study aims to examine relationship between aggregate zones in order to forecast future trips. Moreover, results of modeling trip generation with two different methods, OLR and GWR, are compared. Comparing different levels of aggregation reveals that as the number of zones decreases, the results get better. Decreasing number... 

In response to the growing energy consumptions levels in buildings, many countries have introduced standards and codes aimed at reducing their national building energy consumption levels as well as managing the amount of pollutants. Title 19 of Iran’s National Building Regulation (NBR) was first introduced in 1991. It is projected that Title 19 can lead to a 30 to 50% reduction in the amount of buildings energy consumption. Nevertheless, evidence suggests that the introduction of Title 19 NBR has not led to substantial reduction in building energy consumption in Iran. Unlike Title 19 NBR, similar standards in other countries have proven to be very effective in reducing the building energy... 

In this thesis, we examine different forecasting methods to predict volatility in financial markets. Tehran Exchange Price Index (TEPIX) is adapted to forecast in short and long term periods. TEPIX is the most important index in Tehran Stock Market which is officially reported daily. Autoregressive Integrated Moveing Average models (ARIMA), Generalaized Autoregressive Heteroskedastic models (GARCH) and Artificial Neural Networks (ANN) are used for forecasting TEPIX. Spectral Analysis is also regarded as a completely new approach in financial mathematics to forecast TEPIX in short and long term periods. We consider different criteria to compare the performance of different methods of... 

In this thesis, three popular option pricing models, Black and Scholes Model, Heston Model and Bates Model are compared to each other in economic crises situation. We carry out a comparison between different option pricing models based on S&P500 Index options during 2008. First these data are classified regarding to moneyness and maturity time in nine categories and then the performance of the models, exerting two indexes, In Sample performance and Out Of Sample performance are compared in every category. To reach the prices via In Sample performance index, structural parameters of each model are estimated with the data of each day. Then, daily prices are computed by models and compared with... 

Predicting the price that has the least error and can provide the best and highest accuracy has been one of the most challenging issues and one of the most critical concerns among capital market activists and researchers. Therefore, a model that can solve problems and provide results with high accuracy is one of the topics of interest among researchers. In this project, using time series prediction models such as ARIMA to estimate the price, variables, and indicators related to technical analysis show the behavior of traders involved in involving psychological factors for the model. By linking all of these variables to stepwise regression, we identify the best variables influencing the... 

Iran has the third largest reservoirs of oil and the second largest reservoirs of gas and has the greatest hydrocarbon reservoirs worldwide. Considering the fact that production of oil is highly dependent on gas injection, Iran is facing a great challenge in determining proper strategy for consuming natural gas. Due to the lack of proper strategy form the point of view of economical as well as scientific evaluation in political and social aspects, it has resulted in weakening Iran’s place in international markets and also reduction of oil wells’ productions.In this study, after a review of relevant literature, characteristics of oil and gas projects effective on modeling them were...