Sharif Digital Repository

Given the significance of providing any logical and empirical pieces of evidence to “support the assentation that a test measures the construct as defined and nothing else” (Ary et al., 2013, p. 248), numerous studies have been conducted to investigate construct validity, adopting various approaches. However, there are few studies employing the experimental approach to validation. The current study is aimed at obtaining statistically persuading evidence to answer the question regarding the adequacy of the experimental approach to construct validation, drawing upon the concept of advertising literacy as the construct of the researcher’s concern. To meet this end, the researcher, having... 

Dithiocarbamates have demonstrated extensive applications as synthetic intermediates in the synthesis of functional groups and heterocyclic rings. These compounds, due to their high nucleophilicity, are capable of reacting with a wide range of electrophiles, including aldehydes, alkyl halides, azo compounds, diazo compounds, and many others, yielding diverse and valuable products. This project aims to investigate the reaction of dithiocarbamate salts with fluorinating agents for the synthesis of thiocarbamoyl fluorides. Initially, dithiocarbamate salts were prepared via the reaction of amines with carbon disulfide and the presence of an inorganic base, followed by their conversion to target... 

With the emergence and development of ultra broadband communication systems incorporating ultrashort pulses, the design of suitable receiver structures became one the most significant problems in such systems; since due the limited bandwidth and speed of current electronic devices, most of the existing receiver structures cannot be used properly. In the field of radio communications, the design of simple and low power consumption receivers for ultrawideband (UWB) and millimeter wave band communication systems, which do not rely on complex channel estimation mechanisms, is of much interest. In ultrashort light pulse optical communication systems –and specially coherent optical CDMA systems–... 

Identifying driving behaviors and building an efficient and accurate driving behavior recognition model is of paramount importance for improving driving safety. Nowadays, with the ubiquity of smartphone sensors, many researchers are using smartphone sensory data to create models which forecast driving behaviors. This research introduces a logit model that predicts nine types of driving events using accelerometer and gyroscope sensors with an accuracy of 76 percent  

Wireless Mesh Networks (WMNs) can be considered as the result of cooperation among two ad hoc networks, one composed of Mesh Points (MPs) and another one composed of Mesh Clients (MCs) as well as corresponding Access (Mesh) Points. Each one has its own functions and properties. This cooperation results in a flexible network that to fully demonstrate its potentials, requires special routing algorithms and access schemes.Here, we study and analyze three routing algorithms in IEEE 802.11s-based WMNs from throughput point of view. To this end, each node in the network is modeled by a queue during Contention-Free Periods (CFPs). During Contention-Based Period, however, to simplify modeling, we... 

Sponge Iron production is conducted in various methods that one of them is using coal as a reduction agent. Hoganas process is a different coal-based method that has not been investigated in details. Therefore, the heat transfer method in the system is one of the basic steps to a better recognition of this process (with special Hoganas charging). The present paper investigates the temperature distribution method in the Hoganas cylinder through a numerical model using finite elements. The effects of different parameters, namely preheating and porosity were studied on ceramic crucible made from silicon carbide and it was observed that the consumption energy decreases with the increase of... 

Different causes in the exploration, production and transport of oil in the marine environment result in oil spill events. Since elimination of the probability of occurrence of spills is not possible, it is important to have a plan to control the risk of oil spills by optimal response. In this research, a general stucture is presented for the DSS required for oil spill response planning. This system can be used for evaluation of the effectiveness of response drills, and risk-based ranking of receptor areas and spill sources. Ranking based on risk is realized through probabilistic or stochastic risk assessment. The applicability of the proposed system is examined in differnet case studies in... 

In this thesis, a fault-tolerant method for controlling the relative position and attitude between two satellites in a leader and follower formation is proposed. The follower satellite is equipped with twelve thrusters which are installed on the satellite in a particular pattern. These thrusters are assumed to be afflicted by faults. The satellites are subject to external disturbances – such as the ellipsoidal gravity of Earth (J2), drag force, solar radiation pressure, and the third body, and a controller is designed to attain the desired formation under these disturbances.For this purpose, six separated neural networks are trained, one for each of the position or attitude channels. Since... 

In this research, a dashboard has been developed to support decision-making in the integration of freight companies. Freight companies usually consist of a limited number of vehicles due to the high cost of vehicles, while the fixed costs of a freight company constitute a significant part of that company's total cost. Therefore, if these companies are merged, their total cost will be substantially decreased. Moreover, under particular demand levels, the integration of freight companies reduces the mileage, travel time, and the number of required cars. Therefore, the integration of freight companies not only reduces fixed costs but also reduces other costs including greenhouse gas costs by...