An efficient and low power one-lambda crosstalk avoidance code design for network on chips

, Article Microprocessors and Microsystems ; Volume 63 , 2018 , Pages 36-45 ; 01419331 (ISSN) Shirmohammadi, Z ; Mahdavi, Z ; Sharif University of Technology

2018

Abstract

Crosstalk faults occurring in wires of Networks on Chip (NoCs) can seriously threaten the reliability of data transfer. One efficient way to tackle crosstalk faults is numeral-based Crosstalk Avoidance Codes (CACs). Numeral-based CACs reduce crosstalk faults by preventing specific transition patterns to occur. One-Lambda Codes (OLCs) are the most efficient types of CACs. However, the codec of OLCs imposes overheads including power consumption, critical path and area occupation to the routers of NoCs. To find overhead-efficient OLCs, this paper proposes an Algorithm for Generating OLC Numeral systems (AGON). AGON provides a tradeoff for designers in selecting overhead-efficient OLCs. Using...

Crosstalk Fault Treatment in NoCs Using Data Manipulation

, Ph.D. Dissertation Sharif University of Technology Shirmohammadi, Zahra (Author) ; Miremadi, Ghasem (Supervisor)

Abstract

Recent advances in Very-Large-Scale Integration (VLSI) technologies have enabled designers to integrate a large number of Processing Elements (PEs) on a single die. According to International Technology Roadmap for Semiconductors (ITRS), the number of PEs will reach 5000 on a single die in 2021. Although the main achievements of such rapid advancement in chips are high processing speed, shrinkage of technology size has made chips highly sensitive to different challenges. Networks on chip (NoCs), as an example of these systems, are not exempted from these challenges. Crosstalk fault is one of the major fault resources in NoCs. Crosstalk faults occur due to coupling capacitances between...

, M.Sc. Thesis Sharif University of Technology Shirmohammadi, Davood (Author) ; Movahedi, Mojtaba (Supervisor)

Abstract

Martensitic stainless steels with high strength, good corrosion resistance and formability in the annealed condition are good choices for automotive applications, but they suffer from low weldability due to high hardenability and formation of brittle martensite without tempered structure in the weld metal and heat affected zone (HAZ). In other word, martensitic stainless steels have the worst weldability among all kinds of stainless steels. On the other hand, resistance spot welding is the main method for joining sheets in the automotive industry. Therefore, in the present work, microstructure and mechanical properties of the resistance spot welds of AISI 420 martensitic stainless steel in...

Crosstalk avoidance coding for reliable data transmission of network on chips

, Article 2013 International Symposium on System-on-Chip, SoC 2013 - Proceedings ; 2013 Shirmohammadi, Z ; Miremadi, S. G ; Sharif University of Technology

2013

Abstract

Inter-wire coupling capacitance may lead to crosstalk faults that significantly limits the reliability of NoCs. In this paper, we propose a numerical-based crosstalk avoidance code that can omit the Triplet Opposite Direction (TOD) transitions produced by crosstalk faults. The proposed coding does not have ambiguity and uses all of the codeword space. Simulations using VHDL for different channel widths show that the proposed method can reduce crosstalk fault in the NoC links with negligible power and area overheads

Using binary-reflected gray coding for crosstalk mitigation of network on chip

, Article Proceedings - 17th CSI International Symposium on Computer Architecture and Digital Systems, CADS 2013 ; 2013 , Pages 81-86 ; 9781479905621 (ISBN) Shirmohammadi, Z ; Miremadi, S. G ; Sharif University of Technology

IEEE Computer Society 2013

Abstract

This paper proposes an efficient crosstalk mitigation method for Network-on-Chips. This method uses the binary-reflected Gray coding to send the proper code word into a channel. As the Gray code has reflective and unit distance properties, based on these facts, content of every flit is selected so that to minimize the number of forbidden transition patterns in the channel. A VHDL-based simulation is carried out for several channel widths. Simulation results show that the proposed method reduces the forbidden transitions up to 26% and can save power in NoC links

On designing an efficient numerical-based forbidden pattern free crosstalk avoidance codec for reliable data transfer of NoCs

, Article Microelectronics Reliability ; Volume 63 , 2016 , Pages 304-313 ; 00262714 (ISSN) Shirmohammadi, Z ; Miremadi, S. G ; Sharif University of Technology

Elsevier Ltd 2016

Abstract

Inter-wire coupling capacitances can lead to crosstalk fault that is strongly dependent on the transition patterns appearing on the wires. These transition patterns can cause mutual influences between adjacent wires of NoCs and as a result threaten the reliability of data transfer seriously. To increase the reliability of NoCs against the crosstalk fault, Forbidden Pattern Free (FPFs) codes are used. To generate FPF codes, numerical systems are among the overhead-efficient mechanisms. The algorithms of numerical systems have direct effect on the amounts of the codec overheads including power consumption, area occupation and performance of NoCs. To find an overhead-efficient numerical system,...

Moral Particularism (Dancy's Version)

, M.Sc. Thesis Sharif University of Technology Shirmohammadi, Hamed (Author) ; Miandari, Hassan (Supervisor)

Abstract

There are various versions of moral particularism, this dissertation deals with Jonathan Dancy's version of moral particularism. Dancy's particularism is a meta-ethical view maintains that the possibility of moral thought and judgment does not depend on the provision of a suitable supply of moral principles. This view is in contradiction to generalism. Dancy's particularism has two other main claims: there is no good reason to think that there is any suitable supply of moral principles, and moral principles, if there are any, are not useful. These claims are independent, but each of them depends on the doctrine of holism in the theory of reasons. This doctrine maintains that a feature that...

Optimal Control of Spacecraft on the Earth-Moon Lagrange Point Orbits considering Sun and other Planets and Elliptic Orbit Perturbations

, M.Sc. Thesis Sharif University of Technology Ghorbani, Mehrdad (Author) ; Assadian, Nima (Supervisor)

Abstract

In this thesis, optimal station keeping of spacecraft on the closed-orbits near the Earth-Moon Lagrange points has been investigated. Lagrange points L1 and L2 are unstable equilibrium points of the circular restricted three-body problem (CRTBP), and periodic orbits near them are the destination of modern missions. However, perturbations resulting from the gravitational forces of the Sun and the planets and the eccentricity of the orbit of the Moon around the Earth make the Lagrange point unstable, even L4 and L5, which are stable in CRTBP. The most suitable choice for spacecraft mission near the collinear Lagrange points is the Halo and other closed-orbits around them, which need...

Orbit Design and Optimization of Satellite Constellation for Regional Coverage

, M.Sc. Thesis Sharif University of Technology Borhani, Amir (Author) ; Assadian, Nima (Supervisor)

Abstract

In this thesis, the satellite constellation orbit design for regional coverage is investigated. The orbits of satellites in a constellation for Earth observation missions play a crucial role in performance and characteristics of the mission; for example the image resolution, the area of coverage, and the coverage interval. In this thesis the problem is to find the optimal initial orbital elements for meeting the earth observation mission objectives for one or several sites. The cost functions are the total coverage time, the maximum gap time, time average gap, altitude, and number of satellites. The problem is solved in a multi-objective manner for different combination of two of the above...

Autonomous Orbit Estimation for Regional Navigation Satellites

, M.Sc. Thesis Sharif University of Technology Memaran, Mohsen (Author) ; Asadian, Nima (Supervisor)

Abstract

In this thesis, autonomous orbit estimation of regional navigation satellites has been investigated. Estimation of satellite orbit is an integral part of satellite navigation, which may be executed via assistance of ground station. As the satellite is exposed to the ground station view, range, direction and rate of range is measured by mean of ranging instrumentation relative to ground reference, hence the precise position is calculated. In this thesis a set of satellites are investigated in a unique structure called constellation with the purpose of navigation. The occurrence which is likely to happen in this condition, is the failure of ground station under certain circumstances or losing...

Fabrication and Characterization of a UF Ceramic Membrane based on TiO_2 Nanoparticles

, M.Sc. Thesis Sharif University of Technology Mirkazemi, Amin (Author) ; Taghavinia, Nima (Supervisor)

Abstract

UF membranes are widely used in various industries now, a major type of these membranes are ceramic membranes which are resistant to high temperatures and corrosive fluids. In this thesis we developed an anisotropic UF ceramic membrane based on 20nm TiO2 nanoparticles on a prous sustrate. We had two major challenges, the first one was to find a suitable prous substrate and the second one was to find an appropriate coating method. Our main task was to optimise the process conditions to achive a crackless and uniform membrane layer with minimal ups and downs. Lots of coating methods and TiO2 inks have been tried, finally we used a coating method which we called it “Soft Blade Coating”, with...

Continuous-thrust Trajectory Optimization in the Binary Asteroids System

, M.Sc. Thesis Sharif University of Technology Ashrafi, Mehnraz (Author) ; Asadian, Nima (Supervisor)

Abstract

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...

Fault-tolerant Attitude Control of Sattelite Using Neural Networks

, M.Sc. Thesis Sharif University of Technology Sepehr, Firoozeh (Author) ; Asadian, Nima (Supervisor)

Abstract

This research aims to introduce a new integrated fault tolerant attitude control system of satellites based on the neural networks. First, a linear controller and an optimal controller are designed assuming that no fault occurs in the reaction wheels of the satellite. It is obvious that these controllers are not able to respond properly when a fault occurs. Therefore, artificial neural networks are employed in the fault tolerant controller design. Neural networks are well-known for their adaptiveness and the ability to learn the dynamics of a system. Therefore, they can be used to predict the faulty conditions. In this research two approaches are examined to deal with the faulty conditions....

Fabrication and Characterization of Inverted Perovskite Solar Cells Using Nickel Oxide as Hole Transporting Layer

, Ph.D. Dissertation Sharif University of Technology Saki, Zahra (Author) ; Taghavinia, Nima (Supervisor)

Abstract

In this research, we study and optimize the inverted perovskite solar cells (PSCs) using nano layers of NiOx and Li:NiOx as hole transporting layers (HTLs) and nano layers of PC70BM and C60 as electron transporting layers (ETLs). We fabricated inverted PSCs with three different HTLs, namely MoOx, PEDOT:PSS and NiOx, using vapor assisted solution processed (VASP) method for making MAPbI3 perovskite which yielded a power conversion efficiency (PCE) of 1%, 1.93% and 3.65%, respectively. Solution-processed deposition method, high transparency (˃90%) and high band gap (3.9 eV) are the most advantages to use NiOx as HTL in current research. Using lithium as dopant to the NiOx increases the...

Dynamics of Tethered Satellite Formation Around Binary Asteroids

, M.Sc. Thesis Sharif University of Technology Bakhshipour, Mehran (Author) ; Assadian, Nima (Supervisor)

Abstract

Studying of binary asteroids because of achieving data of existence sources in the world persuades to investigate about tethered satellite formation around binary asteroids in future missions. About 20 percent of asteroids around the sun are binary asteroids. It is going to analyse dynamics of tethered satellite around Didymos binary asteroid. Light mass of the asteroid is good reason to consider gravitational harmonic perturbation, and leads to attention about solar radiation pressure depends on distance in modelling of the dynamical system. It will be zonal harmonics up to second order and sectoral. Satellites are such a particle as an assumption; that is why attitude motion of satellites...

Fractional Order Modeling and Control of Flexible Satellite

, M.Sc. Thesis Sharif University of Technology Hosseini, Masoud (Author) ; Assadian, Nima (Supervisor)

Abstract

In recent decades the structure of space systems has gained more complexity due to the development of space technology. Usage of larger structure in spacecraft could cause undesirable structural vibration. mNeglecting this phenomena would affect the performance of satellite subsystems specially the accuracy of satellite control subsystem. By implementing fractional order calculus in modeling of flexible satellite, the damping effect could be modeled better than classical damping model. Also using fractional order integrator and differentiator operator will increase the performance of control subsystem. In this research, the fractional order calculus has been used in modeling and control of...

Spacecraft Rendezvous and Docking Using Adaptive Neuro-Fuzzy Inference System

, M.Sc. Thesis Sharif University of Technology Tallebi, Morteza (Author) ; Asadian, Nima (Supervisor)

Abstract

In this research an ANFIS controller will be developed to rendezvous and dock with a non-cooperative spacecraft; the controller must make the spacecraft reach the velocity and nearby position of the target spacecraft. Due to uncertainty in modeling and changes in the moment inertia tensor, the controller must be able to adapt with these changes and uncertainty, these changes may happen because of robotic arm or solar panel movings. Robustness of the controller will be evaluated by applying orbital disturbances and modeling errors through monte-carlo simulations. To model the spacecraft the specifications of a known spacecraft will be used but some specifications may be studied parametricaly....

Coupled Rotational and Translational Modelling of Two Satellite Tethered Formation and their Robust Attitude Control

, M.Sc. Thesis Sharif University of Technology Darabi, Atefe (Author) ; Assadian, Nima (Supervisor)

Abstract

The 6DOF modelling and robust attitude control of two tethered satellites using tether tension moments is studied in this thesis. In this regard, the coupled rotational and translational dynamics of two satellites connected by a tether in the presence of Earth’s gravitational perturbation, aerodynamic drag, solar radiation pressure and third body effects (Sun and Moon) and also uncertainties in some of physical parameters of system and sensor’s outputs is modelled. Moreover, the tether attachment point to the satellites is different from their center of mass and its effect on dynamics of the system is taken into consideration. Then, the attitude of both satellites are controlled using robust...

Fault-Tolerant Attitude Control of Satellite with Thrusters Using μ-synthesis

, M.Sc. Thesis Sharif University of Technology Taheri, Abdolreza (Author) ; Assadian, Nima (Supervisor)

Abstract

In this project, a fault-tolerant attitude control system is developed for thruster-driven satellites. The proposed method has the advantage over current state-of-the-art approaches in that it does not require a fault detection and isolation system. Generalized moments are generated by a robust controller that is designed using mixed sensitivity H_∞ and μ-synthesis by DK-iteration. Moreover, a pulse-width modulation technique with quadratic programming optimization is tuned to map the controller outputs to thruster on-off commands as efficiently as possible. The controller is designed to tolerate up to ±30% perturbations in inertia properties and thrust degradations up to 90% of the nominal...

Attitude and Deformation Estimation of Flexible Satellite Using Magnetometer and Sun Sensor

, M.Sc. Thesis Sharif University of Technology Ghani, Marzieh (Author) ; Asadian, Nima (Supervisor)

Abstract

The estimation of attitude and deformation of a flexible satellite using magnetometer and sun sensor data are studied in this thesis. To this end, the dynamical differential equations of the flexible satellite have been derived using Lagrange’s equation. These equations of motion are then utilized for the purpose of simulation and verification. After introducing the measurements equations, the observability of the satellite with flexible panels has been evaluated. Afterward, the attitude of the satellite body and deformation of the flexible panels have been estimated by EKF (Extended Kalman Filter) as well as UKF (Unscented Kalman Filter). The results show that the estimations using UKF are...