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sharifkhani--mohamad
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Systematic Design of Low Power Flash ADC
, Ph.D. Dissertation Sharif University of Technology ; Sadughi, Sirus (Supervisor) ; Sharifkhani, Mohamad (Co-Advisor) ; Atarodi, Mojtaba (Co-Advisor)
Abstract
Considering the drastical increasing of greenhouse gases in the atmosphere, especially carbon dioxide, reduction of these gases seems necessary to combat global warming. Fossil fuel power plants are one of the main sources of CO2 emission. In this thesis, CO2 capture from a natural gas fired combined cycle power plant using different oxygen percent in air feed is studied. Aspen Plus was used to evaluate the effect of this capture technology on the plant efficiency and energetic parameters of the system. Aspen Hysys is used to simulate Amine absorption tower and Air Separation cryogenic tower. Since the oxygen production plant, CO2 capture and transport are cost and energy intensive, the cost...
Developing a Simulator for Concurrent Execution of Multiple Workflows in Fog Computing Environment
, M.Sc. Thesis Sharif University of Technology ; Izadi, Mohamad (Supervisor)
Abstract
Fog computing environment consists of several devices which distribute across an arbitrary topology. Each of these devices is capable of carrying out a designated computation simultaneously with other devices. One of the common ways of describing a computation is through the usage of workflows. Workflow is a flexible and formal way of modeling tasks and their requirements for execution. A workflow is essentially a DAG. Therefore, it can model the data dependency between tasks quite accurately. The complex structure of a workflow in conjunction with the homogenous nature of devices in a fog environment makes it difficult to find a resource management algorithm to minimize execution time, used...
Investigation of the Drop Tank Influence on Range and Optimization of Its Geometry
, M.Sc. Thesis Sharif University of Technology ; Durali, Mohamad (Supervisor)
Abstract
This project focuses on the design of fuel drop tanks for airplanes that add minimal drag and positive lift to the flying object. This will obviously effect the stability and dynamic performance of the airplane. To reduce adverse dynamic effects the tank was divided to several segment with a special emptying sequence. The add-on tank has to have no interference with the object existing systems and require minimum structural changes in the object. Several designs were proposed and the one gaining highest marks was selected. The flow field and the dynamic behavior of combined vehicle and drop tanks were studied using FE simulations. The result shows that adding a drop tank with optimized...
An energy efficient 40 Kb SRAM module with extended read/write noise margin in 0.13μm CMOS
, Article IEEE Journal of Solid-State Circuits ; Volume 44, Issue 2 , 2009 , Pages 620-630 ; 00189200 (ISSN) ; Sachdev, M ; Sharif University of Technology
2009
Abstract
Based on the dynamic criteria for data stability, we introduce segmented virtual grounding architecture with extended read, write noise margin to realize a low leakage current, energy efficient SRAM module. The architecture offers subthreshold operation for the entire module, except for the selected segments. In addition, a new operational mode for the SRAM cell is introduced which allows only the bitlines of the selected columns to be discharged in an operation. The stability of the cells is enhanced in both read and write operation by controlling the cell access time and cell supply voltage, respectively. A 2048$, imes,$20 bit eSRAM unit is implemented in a regular 0.13 $muhbox{m} $ CMOS...
SRAM cell stability: a dynamic perspective
, Article IEEE Journal of Solid-State Circuits ; Volume 44, Issue 2 , 2009 , Pages 609-619 ; 00189200 (ISSN) ; Sachdev, M ; Sharif University of Technology
2009
Abstract
SRAM cell stability assessment is traditionally based on static criteria of data stability requiring three coincident points in DC butterfly curves. This definition is based on static (DC) characteristics of the cell transistors. We introduce the dynamic criteria of cell data stability knowing that the cell operates in a dynamic environment alternating between access and non-access conditions. The proposed definition of the dynamic data stability criteria introduces a new bound for the cell static noise margin (SNM). It reveals that the true noise margin of the cell can be made considerably higher than the conventional SNM once the cell access time is sufficiently shorter than the cell...
A Stochastic Model for Cancer Tumor Growth
, M.Sc. Thesis Sharif University of Technology ; Foroughmand Arabi, Mohamad Hadi (Supervisor) ; Alishahi, Kasra (Co-Supervisor)
Abstract
Cancer can be defined as a stochastic phenomenon. Thus, the tumor growth can be defined as a stochastic process. A Cancer tumor can be analyzed by its geometric shape. Furthermore, computing fractal dimension of shapes is a useful technique to analyze chaosity and complexity of shapes. This approach can be used to compare results from laboratory with simulated results of a mathematical model. A stochastic model of tumor growth will be presented. And some geometrical properties will be analyzed through computer simulation of the model
Bacterial foraging search in unstructured P2P networks
, Article Canadian Conference on Electrical and Computer Engineering ; 2014 ; Pakravan, M. R ; Sharif University of Technology
2014
Abstract
In this paper, a new search algorithm in heterogeneous hierarchical unstructured p2p networks is presented which takes into account heterogeneity of peers such as upload bandwidth, life time in the network and process capacity in its peer discovery policy as factors that influence download performance and user satisfaction. One advantage of this algorithm is that it can be performed in a completely unstructured network without imposing any change on network topology and file replication. However, it obviously decreases file download time as it is designed to discover broad-bandwidth nodes with a higher probability. This property results in a fair distribution of load over heterogeneous p2p...
A review of new advances in resource discovery approaches in unstructured P2P networks
, Article Proceedings of the 2013 International Conference on Advances in Computing, Communications and Informatics, ICACCI 2013 ; 2013 , Pages 828-833 ; 9781467362153 (ISBN) ; Pakravan, M. R ; Sharif University of Technology
2013
Abstract
Since the emergence of peer to peer networks, search efficiency in such networks has been a matter of great concern, as it directly effects resource management of the network and influences users' satisfaction. In unstructured p2p networks, various search algorithms have been proposed so far that offer a tradeoff between scalability, congestion and user's satisfaction. In this paper, we survey newly introduced approaches to overcome search process problems. By reviewing these strategies and comparing them with previous search methods, we propose a new classification of informed search algorithms and we conclude that regarding this classification, informed search algorithms should be applied...
A new metric for comparison of P2P search algorithms
, Article Proceedings - 2012 7th International Conference on P2P, Parallel, Grid, Cloud and Internet Computing, 3PGCIC 2012, 12 November 2012 through 14 November 2012 ; November , 2012 , Pages 191-195 ; Pakravan, M. R ; Sharif University of Technology
2012
Abstract
Success rate, query hit rate and speed of search are some common metrics for evaluating p2p search algorithms. Yet, these metrics do not consider properties of discovered sources and their impact on download performance. A requesting peer is interested in stable serving peers with high upload bandwidth to minimize its download time and therefore, this is the superiority of a search algorithm to find sources with higher upload bandwidth in the p2p heterogeneous environment. In this paper, a new bio-inspired metric for comparing p2p search algorithms is introduced which takes the upload bandwidth of supplying nodes into account as a factor influencing quality of a search algorithm and user...
An Adaptive Low-Power Sense Amplifier with Offset-Cancellation for High-Speed SRAM
, M.Sc. Thesis Sharif University of Technology ; Sharifkhani, Mohammad (Supervisor)
Abstract
A significant large amount of modern SOCs is occupied by SRAMs. Nowadays more than 70% of the Microprocessor area is occupied by SRAMs. This reinforces the need to design a more compact SRAM. With the increase in the processors speed, memories speed needs to be increased to enhance the overall throughput. Current Sense Amplifiers have partially solved the problem. However the area occupied by these amplifiers is still a large amount. The input offset is also not negligible. Due to their cascode configuration, these circuits cannot be scaled with the voltage scaling. In this thesis we proposed a new hybrid sense amplifier with an added phase, so the input offset can be cancelled with a large...
A Novel Bitline Leakage-Free Current Sense Amplifier with Offset Cancelation for Sub-Threshold SRAM
, M.Sc. Thesis Sharif University of Technology ; Sharifkhani, Mohammad (Supervisor)
Abstract
A significant large amount of modern SOCs is occupied by SRAMs. Nowadays more than 70% of the Microprocessor area is occupied by SRAMs. The fast growth of battery-operated portable applications has compelled the SRAM designers to consider subthreshold operation as a viable choice to reduce the power consumption. In most such applications, the speed of the SRAM is not the challenging parameter therefore the thrust toward low power design influence the design choices in various parts of the SRAM architecture. With technology scaling to the nanometer, Bitline leakage current and offset voltage deteriorate SRAM reading performance since SRAM cell current is close to the Bitline leakage current....
Video Shot Boundary Detection
, M.Sc. Thesis Sharif University of Technology ; Sharifkhani, Mohammad (Supervisor)
Abstract
Digital video is one of the biggest part of digital data. The first step of digital video analytics is shot boundary detection. We used overlapped partitioning beside color histogram in uncompressed data and macroblock type prediction in compressed data as feature and supervised classifiers for decision making. Tests on TRECVID 2006 shows 8.9% improvement of F-measure in uncompressed video and 5.3% in h.264 bitstream. Supplementary test is done on IRIB dataset which shows 5.7% improvement of F-measure in uncompressed and 3.2% in H.264. H.264 based algorithm is almost 7 times faster in comparison to the algorithm that includes decoding
Design and Simulation of a Dedicated Analog Circuit to Protect against Power Analysis Attack
, M.Sc. Thesis Sharif University of Technology ; Sharifkhani, Mohammad (Supervisor)
Abstract
With the rapid development of the communication technology, the demand for secure data transferring is inevitable. In this regard, all of secure systems such as Sim-Cards, Smart Cards, to name but a few, enjoy crypto hardware in order to encrypt data. The palpitating heart of these apparatuses, that is, processor, is based on well-known cryptographic algorithms such as AES, RSA, etc. In short, the security depends on the hidden key and in e. g., AES-128 bit, time to disclose the key is in order of 2128. Therefore, no computer can disclosure it in that this period is approximately equivalent to 1032 years in case of the processing computer runs on a 1GHz clock frequency, and a try-out of a...
Design of Integrated Circuit to Extract Energy from Piezoelectric Devices
, M.Sc. Thesis Sharif University of Technology ; Sharifkhani, Mohammad (Supervisor)
Abstract
Energy harvesting from wasted environmental energy to power low-power electronic devices has emerged as an enabling technology for wireless applications in the past decade. The purpose of this technology is to provide remote power sources and/or recharge storage devices such as batteries and capacitors. This concept has environmental implications in reducing chemical waste produced by replacing batteries and potential monetary benefits that also reduce maintenance costs.Energy harvesting (EH) from untapped natural energy sources is common nowadays due to the increasing demand for electricity. Sources have the potential to generate micro to milliwatt power, depending on environmental...
Analysis and Design of a High Speed Embedded SRAM
, M.Sc. Thesis Sharif University of Technology ; Sharifkhani, Mohammad (Supervisor)
Abstract
SRAM has a very wide application in different platforms including Cache Memory in Microcontrollers, etc. also SRAM is the first candidate for memory usage in every application needing High speed or static memory circuits. SRAM Cells are constructed by Minimum size transistors in each technology node and usually the newest technology nodes are used for building SRAM blocks for accommodating maximum number of SRAM Cells in a specific area. Going through smaller technology nodes, Leakage current and Process variations problem, creates serious difficulties in designing Low Power or High speed SRAM Memories and many academic and industrial works are done wishing for improvement in SRAM power...
Efficient Circuit and Systematic Design of Successive Approximation Register Analog to Digital Converters
, Ph.D. Dissertation Sharif University of Technology ; Sharifkhani, Mohammad (Supervisor)
Abstract
Successive Approximation Register (SAR) Analog to Digital Converter (ADC) converts an analog signal to a digital code based on binary search. In contrast to other converters, such as Pipeline and Flash ADCs, most of the SAR ADC components are digital, hence, SAR ADC is technology scalable. Therefore, designed using smaller tehcnologies, SAR ADCs are able to operate at a higher frequency with a lower power consumption and area. The main focus of this thesis is to reduce power consumption, although the proposed techniques and circuits are able to improve other features such as precision, area, or speed.Considering Digital to Analog Converter (DAC), a low-power structure and a novel method to...
Design and Simulation of Integrated Bio-Impedance Driver and Sensor Circuits
, M.Sc. Thesis Sharif University of Technology ; Sharifkhani, Mohammad (Supervisor)
Abstract
Cardiovascular diseases stand as leading contributors to human mortality and disability, with heart muscle diseases, particularly acute and chronic failures, prevalent among them. While various diagnostic methods exist, an accurate, non-invasive, portable, easily accessible, and minimally disruptive approach for monitoring, requiring no frequent clinic visits, takes precedence. Early diagnosis and continuous fluid status monitoring through bioimpedance measurements of chest size are crucial in mitigating the mortality associated with these diseases. Utilizing bioimpedance as a non-invasive signal, this system facilitates ongoing vital parameter monitoring, treatment strategy optimization,...
A Biomechanical Model for Evaluation of Shoulder Function: Detecting the
Relationship Between Muscles Activation Patterns and Shoulder Joint Torques Using Synergy Concept
,
M.Sc. Thesis
Sharif University of Technology
;
Parnianpour, Mohamad
(Supervisor)
;
Asghari, Mohsen
(Supervisor)
Abstract
The effects of combined task demands on the way muscles are recruited to balance external loads during posture and movement is of great importance in quantitative analysis of upper arm function. Pain and disability of shoulder joint is becoming more important as population spends more often interacting with computers in seated position and carrying repetitive tasks using upper extremities. Shoulder joint that is more dependent on the muscles for its normal function than other joints such as hip due to its small articular surface and large range motion has been used here to study its coordination during isometric exertions. Since, the numbers of tasks that could be performed are enormous. In...
A low-power low-offset dynamic comparator for analog to digital converters
, Article Microelectronics Journal ; Vol. 45, issue. 2 , February , 2014 , pp. 256-262 ; ISSN: 00262692 ; Zamani, M ; Sharifkhani, M ; Sharif University of Technology
2014
Abstract
A comparator comprises a cross coupled circuit which produces a positive feedback. In conventional comparators, the mismatch between the cross coupled circuits determines the trade-off between the speed, offset and the power consumption of the comparator. A new low-offset low-power dynamic comparator for analog-to-digital converters is introduced. The comparator benefits from two stages and two operational phases to reduce the offset voltage caused by the mismatch effect inside the positive feedback circuit. Rigorous statistical analysis yields the input referred offset voltage and the delay of the comparator based on the circuit random parameters. The derivations are verified with...
An efficient high-throughput LSI architecture for a synchronization block applied to real-time optical OFDM systems
, Article Proceedings - IEEE International Symposium on Circuits and Systems ; 1- 5 June , 2014 , pp. 1752-1755 ; ISSN: 02714310 ; Shabany, M ; Sharifkhani, M ; Sharif University of Technology
2014
Abstract
An efficient low-complexity VLSI architecture for timing synchronization of a real-time intensity modulation direct detection optical OFDM (IMDD-OOFDM) system is proposed, which results in a significant area reduction. This architecture calculates the correlation among cyclic prefix (CP) regions to estimate the beginning of the OFDM symbol. The proposed architecture utilizes only one functional unit for this purpose, while the throughput is devised for high data-rate optical OFDM systems. Synthesis results of this architecture proves an area saving of 31% compared to the previous work. Moreover, the performance of the correlation method is significantly improved due to a modification applied...