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A fast, flexible, and easy-to-develop FPGA-based fault injection technique
, Article Microelectronics Reliability ; Volume 54, Issue 5 , May , 2014 , Pages 1000-1008 ; ISSN: 00262714 ; Mohammadi, A ; Ejlali, A ; Miremadi, S. G ; Sharif University of Technology
Abstract
By technology down scaling in nowadays digital circuits, their sensitivity to radiation effects increases, making the occurrence of soft errors more probable. As a consequence, soft error rate estimation of complex circuits such as processors is becoming an important issue in safety- and mission-critical applications. Fault injection is a well-known and widely used approach for soft error rate estimation. Development of previous FPGA-based fault injection techniques is very time consuming mainly because they do not adequately exploit supplementary FPGA tools. This paper proposes an easy-to-develop and flexible FPGA-based fault injection technique. This technique utilizes debugging facilities...
Compensation of nonlinearity impairments in coherent optical OFDM systems using multiple optical phase conjugate modules
, Article Journal of Optical Communications and Networking ; Vol. 6, Issue 6 , June , 2014 , pp. 549-558 ; ISSN: 19430620 ; Sharif University of Technology
Abstract
In this paper, we propose utilizing multiple optical phase conjugate (OPC) modules along fiber spans, in order to improve the performance of coherent optical orthogonal frequency division multiplexing (CO-OFDM) communication systems in long-haul fiber-optic channels. The role of OPC in CO-OFDM systems is investigated by formulating the four-wave mixing (FWM) process generated along a CO-OFDM with two and three OPCs. Analytical results reveal that increasing the number of OPC modules reduces the average FWM power along the transmission link and as a result mitigates the degrading effect of interaction between amplified spontaneous emission noise and FWM. The proposed schemes have also been...
Ultra-sensitive detection of leukemia by graphene
, Article Nanoscale ; Vol. 6, issue. 24 , Dec , 2014 , p. 14810-14819 ; Ghaderi, E ; Hashemi, E ; Rahighi, R ; Sharif Universit of Technology
Abstract
Graphene oxide nanoplatelets (GONPs) with extremely sharp edges (lateral dimensions ∼20-200 nm and thicknesses <2 nm) were applied in extraction of the overexpressed guanine synthesized in the cytoplasm of leukemia cells. The blood serums containing the extracted guanine were used in differential pulse voltammetry (DPV) with reduced graphene oxide nanowall (rGONW) electrodes to develop fast and ultra-sensitive electrochemical detection of leukemia cells at leukemia fractions (LFs) of ∼10-11 (as the lower detection limit). The stability of the DPV signals obtained by oxidation of the extracted guanine on the rGONWs was studied after 20 cycles. Without the guanine extraction, the DPV peaks...
Theoretical and experimental investigation of direct detection optical OFDM transmission using beat interference cancellation receiver
, Article Optics Express ; Volume 21, Issue 13 , 2013 , Pages 15237-15246 ; 10944087 (ISSN) ; Chen, L. R ; Zhuge, Q ; Malekiha, M ; Marvasti, F ; Plant, D. V ; Sharif University of Technology
2013
Abstract
We theoretically and experimentally evaluate a beat interference cancellation receiver (BICR) for direct detection optical orthogonal frequencydivision multiplexing (DD-OFDM) systems that improves the spectral efficiency (SE) by reducing the guard band between the optical carrier and the optical OFDM signal while mitigating the impact of signal-signal mixing interference (SSMI). Experimental results show that the bit-errorrate (BER) is improved by about three orders of magnitude compared to the conventional receiver after 320 km single-mode fiber (SMF) transmission for 10 Gb/s data with a 4-QAM modulation using reduced guard band single-sideband OFDM (RSSB-OFDM) signal with 1.67 bits/s/Hz SE...
CLASS: Combined logic and architectural soft error sensitivity analysis
, Article Proceedings of the Asia and South Pacific Design Automation Conference, ASP-DAC ; 2013 , Pages 601-607 ; 9781467330299 (ISBN) ; Chen, L ; Asadi, H ; Tahoori, M. B ; Sharif University of Technology
2013
Abstract
With continuous technology downscaling, the rate of radiation induced soft errors is rapidly increasing. Fast and accurate soft error vulnerability analysis in early design stages plays an important role in cost-effective reliability improvement. However, existing solutions are suitable for either regular (a.k.a address-based such as memory hierarchy) or irregular (random logic such as functional units and control logic) structures, failing to provide an accurate system-level analysis. In this paper, we propose a hybrid approach integrating architecture-level and logic-level techniques to accurately estimate the vulnerability of all regular and irregular structures within a microprocessor....
Effect of chemical substitution on the morphology and optical properties of Bi1-xCaxFeO3 films grown by pulsed-laser deposition
, Article Journal of Materials Science: Materials in Electronics ; Volume 24, Issue 1 , 2013 , Pages 248-252 ; 09574522 (ISSN) ; Mahdavi, S. M ; Nemati, A ; Sharif University of Technology
2013
Abstract
The morphological characteristics as well the optical properties of Ca-doped BiFeO3 films grown by pulsed-laser deposition technique have been investigated. AFM images revealed that calcium has a radical effect on the surface features of BiFeO3 films. By utilizing spectrophotometer, transmission behaviour of the films was investigated. Local IV characteristics of the films disclosed about three orders of magnitude enhancement concerning electrical conductivity through Ca doping. X-ray photoelectron spectroscopy results revealed that Ca can reduce the valence state of iron in the compound
Efficient algorithms to accurately compute derating factors of digital circuits
, Article Microelectronics Reliability ; Volume 52, Issue 6 , June , 2012 , Pages 1215-1226 ; 00262714 (ISSN) ; Tahoori, M. B ; Fazeli, M ; Miremadi, S. G ; Sharif University of Technology
2012
Abstract
Fast, accurate, and detailed Soft Error Rate (SER) estimation of digital circuits is essential for cost-efficient reliable design. A major step to accurately estimate a circuit SER is the computation of failure probability, which requires the computation of three derating factors, namely logical, electrical, and timing derating. The unified treatment of these derating factors is crucial to obtain accurate failure probability. Existing SER estimation techniques are either unscalable to large circuits or inaccurate due to lack of unified treatment of all derating factors. In this paper, we present fast and efficient algorithms to estimate SERs of circuit components in the presence of single...
A new decoding scheme for errorless codes for overloaded CDMA with active user detection
, Article 2011 18th International Conference on Telecommunications, ICT 2011, Ayia Napa, 8 May 2011 through 11 May 2011 ; 2011 , Pages 201-205 ; 9781457700248 (ISBN) ; Pad, P ; Delgosha, P ; Marvasti, F ; Sharif University of Technology
2011
Abstract
Recently, a new class of binary codes for overloaded CDMA systems are proposed that not only has the ability of errorless communication but also suitable for detecting active users. These codes are called COWDA. In [1], a Maximum Likelihood (ML) decoder is proposed for this class of codes. Although the proposed scheme for coding/decoding shows impressive performance, the decoder can be significantly improved. In this paper, by assuming practical conditions for the traffic in the system, we suggest and prove an algorithm that increases the performance of the decoder several orders of magnitude (the Bit-Error-Rate (BER) is divided by a factor of about 400 in some E b/N0's). The algorithm...
Extreme bendability of DNA double helix due to bending asymmetry
, Article Journal of Chemical Physics ; Volume 143, Issue 10 , 2015 ; 00219606 (ISSN) ; Eslami Mossallam, B ; Naderi, S ; Ejtehadi, M. R ; Sharif University of Technology
American Institute of Physics Inc
2015
Abstract
Experimental data of the DNA cyclization (J-factor) at short length scales exceed the theoretical expectation based on the wormlike chain (WLC) model by several orders of magnitude. Here, we propose that asymmetric bending rigidity of the double helix in the groove direction can be responsible for extreme bendability of DNA at short length scales and it also facilitates DNA loop formation at these lengths. To account for the bending asymmetry, we consider the asymmetric elastic rod (AER) model which has been introduced and parametrized in an earlier study [B. Eslami-Mossallam and M. R. Ejtehadi, Phys. Rev. E 80, 011919 (2009)]. Exploiting a coarse grained representation of the DNA molecule...
DiskAccel: Accelerating disk-based experiments by representative sampling
, Article Performance Evaluation Review, 15 June 2015 through 19 June 2015 ; Volume 43, Issue 1 , 2015 , Pages 297-308 ; 01635999 (ISSN) ; Asadi, H ; Sarbazi Azad, H ; Sharif University of Technology
Association for Computing Machinery
2015
Abstract
Disk traces are typically used to analyze real-life workloads and for replay-based evaluations. This approach benefits from capturing important details such as varying behavior patterns, bursty activity, and diurnal patterns of system activity, which are often missing from the behavior of workload synthesis tools. However, accurate capture of such details requires recording traces containing long durations of system activity, which are difficult to use for replay-based evaluation. One way of solving the problem of long storage trace duration is the use of disk simulators. While publicly available disk simulators can greatly accelerate experiments, they have not kept up with technological...
Stereoelectronic effects: A simple yet powerful tool to manipulate anion affinity
, Article Organic and Biomolecular Chemistry ; Volume 13, Issue 7 , Dec , 2015 , Pages 2170-2176 ; 14770520 (ISSN) ; Fattahi, A ; Kass, S.R ; Sharif University of Technology
Royal Society of Chemistry
2015
Abstract
Different strategies are employed in designing strong and selective anion receptors but stereoelectronic effects have been largely ignored. In this work, the stereo configuration of a non-interacting ether is found to have a large impact of more than two orders of magnitude on the binding of a rigid diol with tetrabutylammonium chloride in acetonitrile-d3. A favorable carbon-oxygen dipole and an intramolecular C-H⋯OH hydrogen bond in an equatorially substituted ether is found to be energetically more important than a stabilizing hydrogen bond in the corresponding axially oriented alcohol. IR spectroscopy is also used to probe the structures of the bound complexes and several binding motifs...
Polynomial chaos expansions for uncertainty propagation and moment independent sensitivity analysis of seawater intrusion simulations
, Article Journal of Hydrology ; Volume 520 , January , 2015 , Pages 101-122 ; 00221694 (ISSN) ; Ataie Ashtiani, B ; Simmons, C. T ; Sharif University of Technology
Elsevier
2015
Abstract
Real world models of seawater intrusion (SWI) require high computational efforts. This creates computational difficulties for the uncertainty propagation (UP) analysis of these models due the need for repeated numerical simulations in order to adequately capture the underlying statistics that describe the uncertainty in model outputs. Moreover, despite the obvious advantages of moment-independent global sensitivity analysis (SA) methods, these methods have rarely been employed for SWI and other complex groundwater models. The reason is that moment-independent global SA methods involve repeated UP analysis which further becomes computationally demanding. This study proposes the use of...
A fast analytical approach to multi-cycle soft error rate estimation of sequential circuits
, Article Proceedings - 13th Euromicro Conference on Digital System Design: Architectures, Methods and Tools, DSD 2010, 1 September 2010 through 3 September 2010, Lille ; 2010 , Pages 797-800 ; 9780769541716 (ISBN) ; Miremadi, S. G ; Asadi, H ; Baradaran Tahoori, M ; Sharif University of Technology
2010
Abstract
In this paper, we propose a very fast analytical approach to measure the overall circuit Soft Error Rate (SER) and to identify the most vulnerable gates and flip-flops. In the proposed approach, we first compute the error propagation probability from an error site to primary outputs as well as system bistables. Then, we perform a multi-cycle error propagation analysis in the sequential circuit. The results show that the proposed approach is four to five orders of magnitude faster than the Monte Carlo (MC) simulation-based fault injection approach with 92% accuracy. This makes the proposed approach applicable to industrial-scale circuits
Crosstalk modeling to predict channel delay in Network-on-Chips
, Article Proceedings - IEEE International Conference on Computer Design: VLSI in Computers and Processors, 3 October 2010 through 6 October 2010 ; October , 2010 , Pages 396-401 ; 10636404 (ISSN) ; 9781424489350 (ISBN) ; Miremadi, S. G ; Shafaei, M ; Sharif University of Technology
2010
Abstract
Communication channels in Network-on-Chips (NoCs) are highly susceptible to crosstalk faults due to the use of nano-scale VLSI technologies in the fabrication of NoCs. Crosstalk faults cause variable timing delay in NoC channels based on the patterns of transitions appearing on the channels. This paper proposes an analytical model to estimate the timing delay of an NoC channel in the presence of crosstalk faults. The model calculates expected number of 4C, 3C, 2C, and 1C transition patterns to predict delay of a K-bit communication channel. The model is applicable for both non-protected channels and channels which are protected by crosstalk mitigation methods. Spice simulations are done in a...
Identification of fluid dynamics in forced gravity drainage using dimensionless groups
, Article Transport in Porous Media ; Volume 83, Issue 3 , July , 2010 , Pages 725-740 ; 01693913 (ISSN) ; Kharrat, R ; Pooladi Darvish, M ; Ghotbi, C ; Sharif University of Technology
2010
Abstract
A number of forced gravity drainage experiments have been conducted using a wide range of the physical and operational parameters, wherein the type, length, and permeability of the porous medium as well as oil viscosity and injection rate were varied. Results indicate that an increase in the Bond number has a positive effect on oil recovery whereas the capillary number has an opposite effect. These trends were observed over a two-order of magnitude change in the value of the dimensionless groups. Furthermore, it was found that use of each number alone is insufficient to obtain a satisfactory correlation with recovery. A combined dimensionless group is proposed, which combines the effect of...
Adsorption of proteins at the solution/air interface influenced by added non-ionic surfactants at very low concentrations for both components. 1. Dodecyl dimethyl phospine oxide
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 475, Issue 1 , June , 2015 , Pages 62-68 ; 09277757 (ISSN) ; Javadi, A ; Lylyk, S. V ; Bastani, D ; Fainerman, V. B ; Miller, R ; Sharif University of Technology
Abstract
The adsorption of proteins at liquid interfaces happens at rather low bulk concentrations due to their rather high surface activity. In contrast typical surfactants start to decrease the surface tension at bulk concentration in the range of mmol/l and reach a minimum value at about two or three orders of magnitude higher concentration. The two proteins studied here, β-lactoglobulin and β-casein, adsorb already remarkably at much lower concentrations, i.e. less than 1. μmol/l. When smallest amounts of a non-ionic surfactant are added to low concentrated protein solutions, changes in the surface tension are observed which cannot be explained by the existing theoretical models. An agreement...
Investigating the effects of process variations and system workloads on reliability of STT-RAM caches
, Article Proceedings - 2016 12th European Dependable Computing Conference, EDCC 2016, 5 September 2016 through 9 September 2016 ; 2016 , Pages 120-129 ; 9781509015825 (ISBN) ; Hosseini Monazzah, A. M ; Farbeh, H ; Miremadi, S. G ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
In recent years, STT-RAMs have been proposed as a promising replacement for SRAMs in on-chip caches. Although STT-RAMs benefit from high-density, non-volatility, and low-power characteristics, high rates of read disturbances and write failures are the major reliability problems in STTRAM caches. These disturbance/failure rates are directly affected not only by workload behaviors, but also by process variations. Several studies characterized the reliability of STTRAM caches just for one cell, but vulnerability of STT-RAM caches cannot be directly derived from these models. This paper extrapolates the reliability characteristics of one STTRAM cell presented in previous studies to the...
Influence of perovskite morphology on slow and fast charge transport and hysteresis in the perovskite solar cells
, Article Journal of Physical Chemistry Letters ; Volume 7, Issue 22 , 2016 , Pages 4614-4621 ; 19487185 (ISSN) ; Moshaii, A ; Alizadeh, A ; Gharibzadeh, S ; Mohammadpour, R ; Sharif University of Technology
American Chemical Society
2016
Abstract
We have investigated the influence of perovskite morphology on slow and fast charge transport in the perovskite solar cells. Solar cells with different perovskite cuboid sizes (50-300 nm) have been fabricated using various methylammonium iodide concentrations. Both the low-frequency capacitance and hysteresis are maximum for the cell with the largest perovskite grains (300 nm). The low-frequency capacitance is about three orders of magnitude greater than the intermediate frequency capacitance, indicating the great role of ions on the slow responses and hysteresis. The measurement of open-circuit voltage decay indicates that for the large grains of 300 nm up to 70% of Voc remains across the...
Two-Phase Low-Energy N-Modular Redundancy for Hard Real-Time Multi-Core Systems
, Article IEEE Transactions on Parallel and Distributed Systems ; Volume 27, Issue 5 , 2016 , Pages 1497-1510 ; 10459219 (ISSN) ; Ejlali, A ; Al-Hashimi, B. M ; Sharif University of Technology
IEEE Computer Society
2016
Abstract
This paper proposes an N-modular redundancy (NMR) technique with low energy-overhead for hard real-time multi-core systems. NMR is well-suited for multi-core platforms as they provide multiple processing units and low-overhead communication for voting. However, it can impose considerable energy overhead and hence its energy overhead must be controlled, which is the primary consideration of this paper. For this purpose the system operation can be divided into two phases: indispensable phase and on-demand phase. In the indispensable phase only half-plus-one copies for each task are executed. When no fault occurs during this phase, the results must be identical and hence the remaining copies...
OPTIMAS: overwrite purging through in-execution memory address snooping to improve lifetime of NVM-based scratchpad memories
, Article IEEE Transactions on Device and Materials Reliability ; Volume 17, Issue 3 , 2017 , Pages 481-489 ; 15304388 (ISSN) ; Farbeh, H ; Miremadi, S. G ; Sharif University of Technology
Abstract
SRAM-based scratchpad memories (SPMs) used in embedded systems impose high leakage power. Designing SPMs based on non-volatile memories (NVMs) were proposed as NVMs have negligible leakage power. The main problem of utilizing NVMs across the SPM is their limited number of write cycles (endurance). This problem threatens the reliability of NVM-based SPMs. To alleviate the problem of limited endurance in NVM-based SPMs, this paper proposes a method, called overwrite purging through in-execution memory address snooping (OPTIMAS). The main idea behind the proposed method is to control the lifetime of NVM-based SPMs, directly by a hardware unit, outside of the SPM mapping algorithm. This idea...