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timing-circuits
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Total 105 records
Write invalidation analysis in chip multiprocessors
, Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 9 September 2009 through 11 September 2009, Delft ; Volume 5953 LNCS , 2010 , Pages 196-205 ; 03029743 (ISSN) ; 3642118011 (ISBN) ; Baniasadi, A ; Sharif University of Technology
2010
Abstract
Chip multiprocessors (CMPs) issue write invalidations (WIs) to assure program correctness. In conventional snoop-based protocols, writers broadcast invalidations to all nodes as soon as possible. In this work we show that this approach, while protecting correctness, is inefficient due to two reasons. First, many of the invalidated blocks are not accessed after invalidation making the invalidation unnecessary. Second, among the invalidated blocks many are not accessed anytime soon, making immediate invalidation unnecessary. While invalidating the first group could be avoided altogether, the second group's invalidation could be delayed without any performance or correctness cost. Accordingly,...
Wide-Band RF front end for saw-less receivers employing active feedback and far out-of-band blocker rejection circuit
, Article IEEE Journal of Solid-State Circuits ; Volume 54, Issue 6 , 2019 , Pages 1528-1540 ; 00189200 (ISSN) ; Sharif Bakhtiar, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Elimination of the surface acoustic wave (SAW) filter from the input of a receiver can render it extremely vulnerable to various blockers and interferers. The presence of large out-of-band (OOB) blockers will result in the required linearity of the SAW-less receiver to be considerably higher than that of the conventional receivers with the input SAW filter. The ever-present undesirable signals that arise in the absence of the input SAW filter can be divided into two classes of far and near OOB blockers and interferers. Removal of these harmful signals requires two distinct approaches according to their nature. Two different methods for blocker and interferer rejection are introduced in this...
Wideband and narrowband circuit models for fano-shape guided-mode resonance
, Article IEEE Journal of Quantum Electronics ; Volume 55, Issue 3 , 2019 ; 00189197 (ISSN) ; Memarian, M ; Mehrany, K ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In this paper, we propose two different types of circuit models for Fano-shape guided-mode resonance (GMR) in waveguide gratings. Both the models constitute a resonant tank circuit together with a direct non-resonant channel between the incident and scattered light. One neglects the frequency dependence of the direct non-resonant channel and is only more accurate in the immediate vicinity of the Fano-type resonance. The other accounts for the frequency dependence of the direct non-resonant channel and thus remains accurate within a wider range of frequencies. The former being referred to as the narrow-band model is extremely accurate, insofar as the isolated GMR is of interest within a...
Wide-and narrow-band circuit models for fano-shape guided mode resonance
, Article IEEE Journal of Quantum Electronics ; 2019 ; 00189197 (ISSN) ; Memarian, M ; Mehrany, K ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In this paper, we propose two different types of circuit models for Fano-shape guided mode resonance (GMR) in waveguide gratings. Both models constitute a resonant tank circuit together with a direct non-resonant channel between the incident and the scattered light. One neglects the frequency dependence of the direct non-resonant channel and is only more accurate in the immediate vicinity of the Fano type resonance. The other accounts for the frequency dependence of the direct non-resonant channel and thus remains accurate within a wider range of frequencies. The former being referred to as the narrow-band model is extremely accurate insofar as the isolated GMR is of interest within a narrow...
Wide-and narrow-band circuit models for fano-shape guided mode resonance
, Article IEEE Journal of Quantum Electronics ; 2019 ; 00189197 (ISSN) ; Memarian, M ; Mehrany, K ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In this paper, we propose two different types of circuit models for Fano-shape guided mode resonance (GMR) in waveguide gratings. Both models constitute a resonant tank circuit together with a direct non-resonant channel between the incident and the scattered light. One neglects the frequency dependence of the direct non-resonant channel and is only more accurate in the immediate vicinity of the Fano type resonance. The other accounts for the frequency dependence of the direct non-resonant channel and thus remains accurate within a wider range of frequencies. The former being referred to as the narrow-band model is extremely accurate insofar as the isolated GMR is of interest within a narrow...
When photoluminescence, electroluminescence, and open-circuit voltage diverge-light soaking and halide segregation in perovskite solar cells
, Article Journal of Materials Chemistry A ; Volume 9, Issue 24 , 2021 , Pages 13967-13978 ; 20507488 (ISSN) ; Yang, B ; Kim, Y ; Mohammadpour, R ; Taghavinia, N ; Hagfeldt, A ; Tress, W ; Sharif University of Technology
Royal Society of Chemistry
2021
Abstract
Perovskite solar cells suffer from various instabilities on all time scales. Some of them are driven by light, in particular when employing compounds with mixed halides. Such light soaking effects have been observed to result in performance changes of solar-cell devices. They have also been spectroscopically investigated in detail on films, where the formation of a low-gap iodine-rich phase, seen as a red shift of the PL, has been found to be responsible for a reduced open-circuit voltage. However, studies synchronously examining device performance and its relation to spectroscopy data are scarce. Here, we perform an in operando study, where we investigate the changes of open-circuit voltage...
Voltage balancing of series IGBTs in short-circuit conditions
, Article IEEE Transactions on Power Electronics ; Volume 37, Issue 5 , 2022 , Pages 5675-5686 ; 08858993 (ISSN) ; Peyghami, S ; Iannuzzo, F ; Blaabjerg, F ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
This article proposes a scheme for balancing the voltage of series-connected insulated gate bipolar transistors (IGBTs), which is also very effective under short-circuit conditions. An optimized clamp-mode snubber is proposed, including an active-driver to balance the currents of the IGBTs during short-circuit, which in turn allows for a considerable reduction of the snubber capacitance. The approach is proven to be effective under short-circuit conditions by a maximum of 55 V voltage increment and a negligible difference in the current values. The effectiveness of the proposed approach is demonstrated through simulations in PSPICE software and experimental tests performed at 2 kV. ©...
Timing verification of distributed network systems at higher levels of abstraction
, Article 2008 IEEE International High Level Design Validation and Test Workshop, HLDVT'08, Incline Village, NV, 19 November 2008 through 21 November 2008 ; December , 2008 , Pages 101-107 ; 15526674 (ISSN); 9781424429226 (ISBN) ; Gharehbaghi, A. M ; Hessabi, S ; Sharif University of Technology
2008
Abstract
Nowadays, distributed network systems are broadly using in embedded, real-time and networked control systems. Since they often operate under strict timing constraints, the timing verification is an important and critical phase during the design of them. On the other hand, as contemporary digital systems become more and more complex, taking advantage of the systemlevel design is gaining more widespread acceptance. Beginning from the transaction-level of abstraction is a common and effective method for deploying the system-level design. This paper presents a methodology for evaluation of timing constraints in a distributed network system specified at transactionlevel of abstraction. Timing...
Timing Modulation for Macro-Scale Molecular Communication
, Article IEEE Wireless Communications Letters ; Volume 9, Issue 9 , 2020 , Pages 1356-1360 ; Zlatanov, N ; Gohari, A ; Nasiri Kenari, M ; Mirmohseni, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
In this letter, we propose a novel communication scheme for macro-scale molecular timing channels (MTCs), where the information carrier is the release time of the molecules. Next, the symbol constellation, receiver's sampling time, and receiver's decision rule are designed and analyzed. We further propose a computationally simple yet optimal receiver. Our numerical results show that macro-scale MTC is an approach for achieving ultra-reliable molecular communication. © 2012 IEEE
TherMa-MiCs: Thermal-Aware scheduling for fault-tolerant mixed-criticality systems
, Article IEEE Transactions on Parallel and Distributed Systems ; Volume 33, Issue 7 , 2022 , Pages 1678-1694 ; 10459219 (ISSN) ; Khdr, H ; Gohari Nazari, P ; Ansari, M ; Hessabi, S ; Henkel, J ; Sharif University of Technology
IEEE Computer Society
2022
Abstract
Multicore platforms are becoming the dominant trend in designing Mixed-Criticality Systems (MCSs), which integrate applications of different levels of criticality into the same platform. A well-known MCS is the dual-criticality system that is composed of low-criticality and high-criticality tasks. The availability of multiple cores on a single chip provides opportunities to employ fault-Tolerant techniques, such as N-Modular Redundancy (NMR), to ensure the reliability of MCSs. However, applying fault-Tolerant techniques will increase the power consumption on the chip, and thereby on-chip temperatures might increase beyond safe limits. To prevent thermal emergencies, urgent countermeasures,...
System-level assertion-based performance verification for embedded systems
, Article 13th International Computer Society of Iran Computer Conference on Advances in Computer Science and Engineering, CSICC 2008, Kish Island, 9 March 2008 through 11 March 2008 ; Volume 6 CCIS , 2008 , Pages 243-250 ; 18650929 (ISSN); 3540899847 (ISBN); 9783540899846 (ISBN) ; Gharehbaghi, A. M ; Hessabi, S ; Sharif University of Technology
2008
Abstract
As contemporary digital systems specifically embedded systems become more and more complex, taking advantage of system-level design is being more widespread. Many embedded systems must operate under strict timing constraints. One of the best methods for examining timing constraints in an embedded system can be done via the performance verification. In this paper an assertion-based verification methodology has been proposed for verifying system-level timing constraints in an embedded system. Performance assertions are specified by an assertion language at the transaction-level of abstraction. A Turing machine and a structure named performance evaluator have been coupled to provide a...
Systematic computation of nonlinear bilateral dynamical systems with a novel low-power log-domain circuit
, Article IEEE Transactions on Circuits and Systems I: Regular Papers ; Volume 64, Issue 8 , 2017 , Pages 2013-2025 ; 15498328 (ISSN) ; Soleimani, H ; Drakakis, E. M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
Simulation of large-scale nonlinear dynamical systems on hardware with a high resemblance to their mathematical equivalents has been always a challenge in engineering. This paper presents a novel current-input current-output circuit supporting a systematic synthesis procedure of log-domain circuits capable of computing bilateral dynamical systems with considerably low power consumption and acceptable precision. Here, the application of the method is demonstrated by synthesizing four different case studies: 1) a relatively complex 2-D nonlinear neuron model; 2) a chaotic 3-D nonlinear dynamical system Lorenz attractor having arbitrary solutions for certain parameters; 3) a 2-D nonlinear Hopf...
Surface engineering of TiO2 ETL for highly efficient and hysteresis-less planar perovskite solar cell (21.4%) with enhanced open-circuit voltage and stability
, Article Advanced Energy Materials ; Volume 8, Issue 23 , 2018 ; 16146832 (ISSN) ; Yadav, P ; Tavakoli, R ; Kong, J ; Sharif University of Technology
Wiley-VCH Verlag
2018
Abstract
Interfacial studies and band alignment engineering on the electron transport layer (ETL) play a key role for fabrication of high-performance perovskite solar cells (PSCs). Here, an amorphous layer of SnO2 (a-SnO2) between the TiO2 ETL and the perovskite absorber is inserted and the charge transport properties of the device are studied. The double-layer structure of TiO2 compact layer (c-TiO2) and a-SnO2 ETL leads to modification of interface energetics, resulting in improved charge collection and decreased carrier recombination in PSCs. The optimized device based on a-SnO2/c-TiO2 ETL shows a maximum power conversion efficiency (PCE) of 21.4% as compared to 19.33% for c-TiO2 based device....
Stability analysis of the Euler-Bernoulli beam with multi-delay controller
, Article Control Theory and Technology ; Volume 20, Issue 3 , 2022 , Pages 338-348 ; 20956983 (ISSN) ; Xu, G ; Effati, S ; Sharif University of Technology
South China University of Technology
2022
Abstract
In this paper, we investigate the stabilization of an Euler-Bernoulli beam with time delays in the boundary controller. The boundary velocity feedback law is applied to obtain the closed-loop system. It is shown that this system generates a C-semigroup of linear operators. Moreover, the stability of the closed-loop system is discussed for different values of the controller constants and time delays via using spectral analysis and a suitable Lyapunov function. © 2022, The Author(s), under exclusive licence to South China University of Technology and Academy of Mathematics and Systems Science, Chinese Academy of Sciences
Stabilisation of multi-loop amplifiers using circuit-based two-port models stability analysis
, Article IET Circuits, Devices and Systems ; Volume 15, Issue 6 , 2021 , Pages 553-559 ; 1751858X (ISSN) ; Meghdadi, M ; Medi, A ; Sharif University of Technology
John Wiley and Sons Inc
2021
Abstract
This article applies a systematic approach based on the normalized determinant function (NDF) theory to analyse stability in multi-loop circuits and to design the required stabilization network. Presenting several provisions, the return ratios are extracted by employing immittance or hybrid matrices (Z, Y, G or H) of active two ports. Using these matrices, instead of the S-parameters, facilitates the selection of an appropriate stabilizer network. As a practical case, a non-uniform distributed amplifier (NDA) is designed and inspected for potential instabilities. The presented procedure detects instability associated with one of the NDA circuit's loops, and an appropriate stabilization...
Simultaneous leaching of Cu, Al, and Ni from computer printed circuit boards using Penicillium simplicissimum
, Article Resources, Conservation and Recycling ; Volume 177 , 2022 ; 09213449 (ISSN) ; Arshadi, M ; Yaghmaei, P.O. C. A. P. E. D. S ; Sharif University of Technology
Elsevier B.V
2022
Abstract
A short lifespan and increased consumption patterns make e-waste the world's fastest-growing waste stream. Computers are one of the most significant parts of e-waste. Recycling of e-waste has been introduced as the main solution to deal with environmental problems and to save natural mines. This research aims to investigate the bioleaching of Cu, Ni, and Al from computer printed circuit boards (CPCBs) using Penicillium simplicissimum. The adaptation phase began at 1 g/l CPCBs powder with 107 spores and final pulp density was reached at 30 g/l. The most effective parameters including pulp density, initial pH, and the sucrose concentration were optimized to achieve maximum simultaneous...
Short-circuit analysis in three-phase quasi-Z-source inverter
, Article 17th IEEE International Conference on Environment and Electrical Engineering and 2017 1st IEEE Industrial and Commercial Power Systems Europe, EEEIC / I and CPS Europe 2017, 6 June 2017 through 9 June 2017 ; 2017 ; 9781538639160 (ISBN) ; Moghani, J. S ; Noroozi, N ; Zolghadri, M. R ; IEEE EMC Society; IEEE Industry Applications Society (IAS); IEEE Power and Energy Society (PES) ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
In this paper, the short-circuit fault in three-phase quasi-Z-source inverter (q-ZSI) is analyzed and a linear model is proposed for the short-circuit analysis. The proposed model is based on the state space equations of the system. By using this model, the most critical situation during short-circuit fault is recognized; the maximum reaction time for the protection system could be estimated and elements that are prone to failure are identified as well. The analysis is categorized into two groups, leg fault and switch fault. The linear model is confirmed by simulation of 1kw three-phase q-ZSI. © 2017 IEEE
Self-Powered soil moisture monitoring sensor using a picoampere quiescent current wake-up circuit
, Article IEEE Transactions on Instrumentation and Measurement ; Volume 69, Issue 9 , 2020 , Pages 6613-6620 ; Habibi, M ; Magierowski, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
Low-power wireless stand-alone sensors that can operate without any wiring have received significant attention in sensor network applications. These devices harvest environmental energy resources to supply their power and transfer their collected data using wireless RF links. In many instances, the power supplied from the environment is far less than the power required by the sensor device. In this case, the main solution is to accumulate energy on a storage element, and when enough energy is stored, the sensor node is instantaneously activated using an undervoltage lockout (UVLO) circuit. During this short time burst, the sensor performs the required acquisition, transmits the results, and...
Secure two-party computation using an efficient garbled circuit by reducing data transfer
, Article 8th International Conference on Applications and Techniques in Information Security, ATIS 2017, 6 July 2017 through 7 July 2017 ; Volume 719 , 2017 , Pages 23-34 ; 18650929 (ISSN); 9789811054204 (ISBN) ; Farzam, M. H ; Bayat Sarmadi, S ; Sharif University of Technology
Springer Verlag
2017
Abstract
Secure computation has obtained significant attention in the literature recently. Classic architectures usually use either the Garbled Circuit (GC) or the Goldreich-Micali-Wigderson (GMW) protocols. So far, to reduce the complexity of communications in these protocols, various methods have been proposed. The best known work in both methods reduces the communication up to almost 2k-bits (k is the symmetric security parameter) for each AND gate, and using XOR gate is free. In this paper, by combining GC and GMW, we propose a scheme in the semi-honest adversary model. This scheme requires an Oblivious Transfer (OT) and a 2-bit data transfer for each AND gate, keeping XOR gates free. The...
Quick diagnosis of short circuit faults in cascaded H-bridge multilevel inverters using FPGA
, Article Journal of Power Electronics ; Volume 17, Issue 1 , 2017 , Pages 56-66 ; 15982092 (ISSN) ; Zolghadri, M. R ; Rodriguez, J ; Shahbazi, M ; Oraee, H ; Lezana, P ; Schmeisser, A. U ; Sharif University of Technology
Korean Institute of Power Electronics
2017
Abstract
Fast and accurate fault detection is the primary step and one of the most important tasks in fault tolerant converters. In this paper, a fast and simple method is proposed to detect and diagnosis the faulty cell in a cascaded H-bridge multilevel inverter under a short circuit fault. In this method, the reference voltage is calculated using switching control pulses and DC-Link voltages. The comparison result of the output voltage and the reference voltage is used in conjunction with active cell pulses to detect the faulty cell. To achieve this goal, the cell which is active when the Fault signal turns to “0” is detected as the faulty cell. Furthermore, consideration of generating the active...