Melika Morsali

Ms. Melika Morsali

Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, Virginia, USA
orcid

Research Focus & Metrics

Academic Career Length

1Year (2026-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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25 May 2025
Verified
Conference Paper
Closed access
RSR. Sreekumar
R. Sreekumar
MMMelika Morsali
Melika Morsali
NSNaomi Solomon
Naomi Solomon
YGY. Gao
Y. Gao
MPM. Park
M. Park
MSMircea R. Stan
Mircea R. Stan
Traditional edge accelerators struggle to balance performance, accuracy, and power consumption. Our solution leverages Asynchronous Stream Computing (ASC) to implement a fully asynchronous, clockless system where data is encoded in the frequency and duty cycle of streams. This architecture adapts dynamically to available energy resources, adjusting computational precision and speed in response to workload demands. A stimulus-driven model allows the system to process data efficiently when actionable information is present. Analytical and experimental results highlight a tunable trade-off between latency and precision, aligning system performance with real-time requirements. To validate these concepts, we implement a Compute-in-Memory (CiM) based dot product architecture to accelerate Word2Vec Algorithms for Natural Language Processing (NLP) tasks and have exhibited a relative semantic accuracy scaling of 47.81% and a computational efficiency scaling of 43.23x when scaling precision from 12 - 4 bits.

1 August 2026
Verified
Conference Paper
Closed access
MMMelika Morsali
Melika Morsali
HYHacer Atar Yildiz
Hacer Atar Yildiz
MSMircea R. Stan
Mircea R. Stan

30 October 2026 in Micromachines
Verified
Journal Article
Open access
PDF file
MMMelika Morsali
Melika Morsali
PCPranav Choori
Pranav Choori
EAEthan C. Ahn
Ethan C. Ahn
MSMircea R. Stan
Mircea R. Stan
Filamentary metal–oxide RRAM conducts through a tunneling gap for which the current grows exponentially with bias, so its Read-range I–V characteristic follows a sinh(V/V0) law. This introduces a systematic, input-dependent multiply–accumulate (MAC) error when used in analog Compute-in-Memory (CiM) accelerators with inputs encoded as voltage amplitudes. Because the nonlinearity also varies with resistance state, a single correction factor cannot generally compensate for all programmed weights. We present a measurement-calibrated device-to-circuit study of this error and show how it can be mitigated by replacing voltage-amplitude inputs with fixed-bias time-domain inputs, as in Asynchronous Stream Computing (ASC), which uses constant-amplitude sigma–delta streams. RRAM samples from two independent processes, Pt/Ti/HfO2/Ta/Pt and Al/TiO2/Au/Ti, are characterized, and the Stanford compact model is calibrated to each process. Together with two published parameter sets, the fitted nonlinearity coefficient V0 spans 0.29–0.55 V across four stacks and varies with resistance state within individual devices. In 65 nm circuit simulations, voltage-amplitude encoding incurs up to 30% relative error in a single cell and approximately 8.5% full-scale-normalized error in single-bitline crossbars of 4 to 256 rows. At a 5 ms accumulation window, ASC reduces the array error to 0.4–0.8% with ideal-integrator readout and 0.8–2.3% with transistor-level AΣΔM readout. Under measured device variability, group-balanced Monte Carlo simulations yield 7.6–9.2% analog error versus 0.5–0.7% ASC error. Wire resistance reduces the fixed-bias advantage but does not eliminate it within the simulated conditions. First-order energy estimates identify accumulation time and cell read current as important costs, while practical implementation also requires wordline drivers and high-ratio current division.