Sharif Digital Repository

The present study simulates the diffusion of nitrogen oxides from a typical thermal power plant by AERMOD. The amount of diffusion of nitrogen oxides in the environment in two sample days was assessed, one in the cold season and the other in the warm season. In the pessimistic state of the power plant on the sample day of the warm season did not cause the ambient concentration to exceed the standard level of clean air.In order to evaluate the share of different emission sources in the study area, emission sources are divided into three groups: industrial, suburban transportation and urban resources (domestic and intra-city transportation) and two modes of emission are considered. On the... 

Nowadays, by integrating the Internet of Things systems into the daily life of humans, mankind has created a platform for providing numerous and diverse services through which life has become much simpler and more convenient. These systems have gradually become an integral part of today's life. They are used in many areas of production and service provision, such as healthcare, agricultural industry, supply chain, education system, transportation, and many others. Although these achievements have facilitated human life in many aspects, they are also associated with many security risks. Intrusion detection systems (IDS) are methods for predicting possible damage (through security attacks such... 

The application of membranes for separate of particles in mainly microbial flacs , are fast growing in biological treatment systems. Membrane bioreactors are now considered as one of the major new processes in wastewater treatment. However , membranes are expensive and costly. This study is carried out to test an innovative , locally made filters for separation of flocs in an MBBR reactor. This innovative filter is replacing a traditional settling tank. This type of filters is made very cheaply and has important advantages in installing and operation. Experiments were carried out in a laboratory scale MBBR unit. A filter unit consisting of 3 innovative filter tubes were placed and the... 

In this thesis, the optimal trajectories of a spacecraft in the binary asteroids system is studied. The objective functions of optimal trajectories in these system are the maximum coverage of the asteroids surface and minimum time and fuel consumption. For this purpose, the dynamic of binary system is modeled. The binary system of 1999 KW4 is selected as a case study. The ellipsoid-sphere model is a good approximation for the case of this study. In this model, the asteroids orbit in a circular orbit around each other in a spin-spin-orbit resonance configuration, in which the asteroids’ rotational velocity is equal to orbital mean motion. Then, the equations of motion of the spacecraft as the... 

Providing multimedia content to the end-user is one of the most challenging tasks in today’s digital world. Therefore choosing the best media compression method is both technically and economically important. In the context of audio codecs, MPEG-4 HE-AACv2 is capable of providing very high quality output at very low bitrates. 3GPP Enhanced aacPlus is one of the practical implementations of this codec, which is extensively adopted by several telecommunication standards as the main audio compression algorithm.
Nowadays almost every cell phone and portable digital media player includes a DSP. The C6000 family of DSPs from Texas Instruments has been exploited for the purpose of this... 

Embedded SRAM unit is recognized as an important block in the systems on chip. In recent years due to an abrupt increase in the number of such systems which often work with battery, the priority of designing of low power circuits has been increased. Furthermore, increase in the number of transistors in the SRAM and increase in leakage current of MOS transistors with technology scaling have rendered the SRAM into the main energy consumer (from both static and dynamic view).In the writing operation due to the full swing of bit line, the dynamic power forms the main chunk of the consumptive power. The static consumptive power mostly happens due to the leakage current of broken cells in an array... 

Sigma-delta modulators have largely been implemented as discrete-time (DT) circuits because of their low sensitivity to circuit nonidealities, and their frequency scaling specification, however a continuous-time (CT) design offers significant advantage in the design of high accuracy, high speed analog to digital converters (ADC). A CT design allows for relaxed amplifier(s) bandwidth and power requirements, which enables the realization of high accuracy modulators with bandwidths of several megahertz at low power consumption. Furthermore CT modulators provide inherent anti-aliasing filtering which becomes especially important at low oversampling ratios. This thesis reports the design of a... 

This thesis presents a new approach to feedback active noise cancellation. The problem of Reducing the noise level in the environment has been the focus of research over the years. Active Noise Cancellation (ANC) is one such approach that has been proposed to eliminate Noise. ANC refers to an electro acoustic approach of canceling acoustic disturbance to Produce a quieter environment. The basic principle of ANC is to introduce a canceling “anti Noise” signal that has the same amplitude but the exact opposite phase, thus resulting in Reducing the remainder noise signal. We use neural networks based on system identification And predict control to cancel acoustic noise. Canceling acoustic... 

There are three types of Slices in an FPGA, and based on the functionality of these slices, SliceM has the most features especially for designs based on shift registers, adders, and ROMs, and from all of the slices, 25% of them are SliceM. Among the earlier designs that are FPGA-based, Anderson PUF is that is classified as a weak delay-based PUF. In Anderson’s design there always should be atleast two SliceMs that their LUTs are configured as shift registers, the Andersons PUF in some FPGA Architecture especially Series 7 FPGAs, consumes two SliceMs and two other SliceLs, so practically we are using four of our precious slices. Rather than these, in series 6 FPGAs, the design should change... 

This work uses a hierarchical approach for designing the integrated UWB LNA in MOSFET technology. It first offers a brief treatment of the two important types of noise: the thermal noise of channel and the gate-induced noise, in MOSFET. Then the CS and CS-CG configurations for narrow-band LNAs are considered and the requirements for the wide-band operation in UWB are specified. Noise cancelling technique is also introduced, while five wideband prototype designs, with the noise-cancelling technique used in two designs, are re-examined and tested by simulation. Some proposed methods are then applied to these designs for better performance and obtaining practical insight. The final main... 

Predicting the location of oil and gas recourses is the first challenge in the petroleum industry. One of the most popular and acceptable ways which can guide an explorer to the position of the resources is the seismic survey. By this kind of survey, geologists can observe inside of solid matter by using the ultrasound waves. The process works by sending sound waves to the surface and measuring the length it takes to be reflected from rocks underneath, then with recording these echoes by arrays of sensors, they can obtain a seismic image which has too noise, including ghosting, multiples (multiples are the waves that has been reflected more than once between the energy source and the... 

Determining the porosity, water saturation and permeability values in the reservoir rock, are major steps in the petroleum engineering and formation evaluation. Today in the oil industry, these parameters are obtained using Helium gas injection technique on core (Plug) samples. However, the coring operation is difficult and costly. In addition, there isn't the possibility of coring in some of wells, such as horizontal wells. In fact, the present research is the modelling of artificial neural networks to estimate permeability in one of the Iranian oil field reservoirs by using oil well logging data. In this research, MLP neural network has been used and for network training, the evolutionary... 

Friction drilling or flow drilling is a method of making holes in metal sheets, in which the material is pushed with the aid of heat from friction. This procedure allows making holes in sheet metal, with a sleeve formed as the hole is created. This sleeve is then threaded and used as the nut, thus eliminating the need for access to the interior faces of hollow steel sections. On the other hand, with the development of advanced manufacturing techniques, larger and thicker hollow structural sections are becoming more popular in mid-rise and multistory structures. onsequently, flow drilling can be considered as a viable alternative for traditional drilling techniques, where the material is... 

High resolution and low power analog to digital converters are used in wireless communication receivers, Sensor Networks and Medical Instrumentations. Reducing power consumption at a high conversion rate is one of the most basic challenges for these converters. Pipelined SAR structure is considered for 40-50 MS/s and 10-12 bits, and is of interest because of consuming low power and using a small area. Besides using Pipelined SAR structure, circuit level and system level modifications are also proposed to decrease the power consumption. The ADC is designed in 0.18µm CMOS technology with 1.2v supply voltage. The results show 4.5mW power consumption, when ENOB is 11.04bit, which is very low... 

Pipelines are the preferred means for transporting of liquid or gas phase materials. The economy of many countries is extremely dependent upon a large network of pipelines systems to transport and distribute the nation’s energy resources. Damages to the pipe structure may cause leakage and result in economic losses or even loss of life. Developing methods for detecting the anomalies and damages to the structure before they lead to catastrophic events is vital. Multiple pipeline misadventures over the past several years have resulted in hundreds of fatalities and billions of dollars in property damages. These accidents demonstrate that the current monitoring methods are not sufficient... 

High speed data converter are very often used in telecommunication systems. Since these systems are increasingly used in mobile foem reducing the power consumption in these circuits is of great importance. The goal of this project was to design a pipeline 10 bit converter for a sample rate 200MS/s with a power consumption of 35 mW for the input level of 1Vp-p and a 1.8V power supply in 0.18um CMOS technology.
To reach these goals, a number of low power techniqes are proposed in various levels of abstraction. In system level, the sampling and feedback capacitors is optimized analytically which leads to simple back-envelope formulas to calculate the optimum values. In circuit level, a... 

In recent years with the increase of cellular phone subscribers, demand for high capacity networks is inevitable. For this reason, different methods have been proposed to increase the channel capacity. One method which has become popular in recent years is utilizing of Smart Antenna Systems. Smart antennas basically attempt to enhance the desired signal power and suppress the interferers by beamforming toward the DOA (direction-of-arrival) of the desired signal and nullsteering in the interferences’ DOAs. Smart Antennas first find the direction of signal sources, and then put the main gain toward the desired signal and put the nulls toward unwanted signals. As a result, we can obtain the...