Sharif Digital Repository

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... 

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... 

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... 

Concerns like fuel cost, pollution and global warming has made it necessary to look for new energy solutions. Renewable and alternative energies have proven themselves to be helpful in this matter. Renewable energy(RE) is the energy that comes from natural resources such as sunlight, wind, rain, tides, waves and geothermal heat, which are naturally replenished at a constant rate. Renewable energies are environmentally friendly, not cheap at the beginning but naturally available in a constant rate and wide spread, unlike fossil fuels that are localized in the limited places. In this thesis in order to generate environmental friendly power we consider two renewable energy resources: wind and... 

The explosive growth of battery operated devices has made low-power design a priority in recent years. Moreover, embedded SRAM units have become an important block in modern SoCs. The increasing number of transistor count in the SRAM units and the surging leakage current of the MOS transistors in the scaled technologies have made the SRAM unit a power hungry block from both dynamic and static perspectives. One of the key strategies for reducing power consumption is reducing the supply voltage to near or below the threshold voltage of the transistor. However, as supply voltage decreases to tackle the power consumption, the data stability of the SRAM cells have become a major concern in recent... 

A large number of sensors are spread for monitoring of an area in a random manner. The aim is to have an efficient design for energy that can protect the coverage of the area. A number of sensor nodes that have high density and which are in the area have the duty of monitoring of the area. The aim of this process is to determine of maximum number of separate collections that they have a direct influence upon the life span of the network. The idea behind this approach is that the nodes in areas with low availability are less used as a data routing as well as nodes that have remaining energy. In order to reach this objective, the importance of each sensor node for its duty of protecting... 

Growing demand for increased data transmission in communication systems and the internet, has intensified the need to increase the bandwidth of high speed transceivers. One of the main elements in high speed receivers is the clock and data recovery circuit which guarantees the transfer of data with high reliability. In this thesis, the design of a clock and data recovery circuit for high frequency applications is considered. The aim of this project is the design of a circuit with low power and low jitter for high-speed input data. A new four stage LC ring oscillator is designed that works at the quarter rate of the input. A new idea for the design of the binary phase detectors has also been... 

Some applications need fast locking clock and data recovery circuits for example the circuits that operate in burst mode must lock to the data packets which are transmitting from different transmitters very quickly and in just a few bit times. In such applications open-loop clock and data recovery circuits are used because lock time in closed-loop clock and data recovery circuits is usually much longer.
In this thesis a new open loop clock and data recovery circuit based on injection locking method has been proposed. This circuit can be used in applications such as passive optical networks that need fast locking. In this architecture a super harmonic injection-locked frequency divider... 

Analog to digital converters are one of the most important component of Bluetooth and GSM receivers. The pipeline and Successive Approximation Register (SAR) ADCs are mainly used in these receivers. However, the pipeline ADCs consume lots of power and SAR ADCs suffer the resolution in advanced technologies. On the other hand, the Delta-Sigma ADCs are capable of achieving high resolution with a low power. So in this thesis, the various kinds and different implementations of Delta-Sigma Modulators are introduced. The system level design and the conversion between Discrete-Time Modulators and Continuous-Time Modulators are explained. The non-ideality effects such as limited gain and bandwidth... 

SAR image noise is a significant problem for SAR image analysis.The inherent noise of SAR images, known as speckle, seriously affects the SAR image interpretation. It also has adverse effects on the classification and segmentation of SAR images. Due to its great significance, the SAR image processing has received considerable attention in recent years and many researchers have developed techniques to reduce the inherent noise accompanying the SAR images. A survey of the literature shows that the wavelet analysis is one of the most common methods used for speckle reduction. While the power of the morphological analysis method has mostly not been recognized, we have utilized this efficient... 

Polypropylene plants receive propylene monomer and produce polypropylene polymer by inducing chemical reactions under high pressure and high temperature conditions. In these plants it is essential to monitor and carefully control the density and level of the material contents in slurry high pressure and high temperature reactors and vessels. Due to process conditions and the advantages of the non contact measuring method we use radioactive level and density measurement method specially gamma ray level and density detectors and transmitters in P.P plants. Sometimes, however known and unknown natural or manmade factors may affect the performance of these devices. The known factors such as NORM... 

Effect of resolution of Time to Digital Converters (TDCs) on the performance of All-Digital Phase Locked Loops (ADPLLs) and capability of achieving higher resolution in advanced technologies lead to introducing different kinds of TDCs. Beside the analysis of different kinds of TDCs, This thesis proposes three new TDCs based on the time amplifi-cation concept. A new pipeline TDC is designed using a wide dynamic range time amplifi-er. A new method is used to widen dynamic range of the conventional time amplifiers. In order to get a low power high resolution conversion, a new delay element design is devel-oped to reduce the delay value and its sensitivity to mismatch and process variations.... 

Many applications that require heavy processing, such as augmented reality, facial recognition, self-driving cars, and digital healthcare systems, are emerging. Many devices in the Internet of Things space cannot process such a volume of calculations. One of the newest methods to solve this problem is using new architectures in network design, among which we can refer to the edge computing architecture. In this method, by offloading the computation on the available computing resources close to the network's end nodes, we try to provide the results of the calculations for the end nodes of the network as quickly as possible. In this thesis, the problem of determining the computation offloading... 

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... 

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... 

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... 

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... 

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... 

In this thesis, A novel approach for ¼-rate clock Phase Detector (PD) structure for Phase Locked Loop (PLL)-based Clock and Data Recovery (CDR) is proposed. In this approach, the retimed data is generated within the circuit and no extra circuit is needed. Another advantage of this topology is that the error and reference signals are independent of delay time through gates and no extra replica circuit is needed to compensate the delay. This topology results in a lower power circuit and smaller area for high speed application compared to conventional topologies  

In this research non-contact ultrasonic based method is used for liquid level measurement in a container. A system has been designed and developed to determine the liquid level and show the results on a personal computer. The system contains three main parts, which are mechanical and electronic parts and the programming. The setup can measure the liquid level with the accuracy of 1cm. An ATMEGA8 microprocessor commands to relays and controls the pumps. The pumps are used to change the height of the liquid in the containers to accurately calibrate the sensor and test its operation. The ultrasonic sensor, which is mounted above the vessel, transfers the data to an ATMEGA64 microprocessor for...