EDBT 2026 Demo / reviewers in the wild / expert
Siva Satyendra Sahoo
dblp:179/2952
· DBLP profile ↗
28ranked-venue papers
13as first author
21since 2021 · last 2025
0000-0002-2243-5350ORCID · verified
Domains — the database's venue-derived domains; a paper can count in several
Systems, architecture and hardware · 28 · 13 first-author · 21 since 2021Software engineering, systems software and programming languages · 3 · 1 first-author · 1 since 2021
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2025 | SpiRec: Soft-Logic Architecture Exploration of Reconfigurable Systems for Spiking Neural NetworksabstractIn recent years, Spiking Neural Networks (SNNs) have been increasingly deployed on Field Programmable Gate Arrays (FPGAs) for enabling low-energy AI inference. SNNs aim to enable more biomimetic processing than ANNs, thereby enabling more event-driven computing along with using cheaper arithmetic than multiply and accumulate operations. However, deploying large SNNs to achieve acceptable accuracy requires extensive use of configurable logic blocks (CLBs), leading to additional programmable routing and critical path delay. This study addresses these issues by exploring soft-logic architectures to reduce resource utilization for SNNs. We propose two architectures that provide a more efficient mapping of logic primitives for SNNs, reducing CLB usage by 13.49% and 20.13% compared to the Intel Stratix10 baseline. Implemented with an advanced technology node, these architectures achieve an average reduction of 8.30% and 7.30% in CLB area and reduce critical path delay by 2.72% and 3.42%, respectively, enabling larger SNNs with faster inference within the same programmable fabric. Xunqin Lai, Federico Corradi, Siva Satyendra Sahoo |
ASAP | 3 |
| 2025 | Special Sessions - Emerging Scope and Design Challenges for Approximate Computing: Optimizing Accuracy-PPA trade-offs and BeyondabstractThe rapid growth of AI workloads is driving interest in Approximate Computing (AxC) as a means to enable low-cost, energy-efficient inference in resource-constrained systems. By introducing controlled inaccuracies, AxC can deliver substantial gains in power, performance, and area (PPA) while leveraging the inherent error tolerance of many AI models. Achieving this potential requires adapting existing frameworks to support the design and optimization of neural networks with approximate operators. Modern AxC research extends beyond accuracy-PPA trade-offs to address reliability and security, reducing redundancy overheads and exploring the distinctive side-channel implications of approximation. Application-aware approaches, such as those for spiking neural networks, show that tailoring approximation to workload-specific error behavior can surpass generic strategies. This article examines AI-guided design methods and the interplay between efficiency, reliability, and security, highlighting how these interconnected facets can advance embedded and high-performance computing. Siva Satyendra Sahoo, Bastien Deveautour, Marcello Traiola, Chongyan Gu, Yun Wu 0003, Aditya Japa, Salim Ullah, Akash Kumar 0001 |
CASES | 1 |
| 2025 | Design, Model, and Explore Approximate Arithmetic Operators with AI/ML: A TutorialabstractApproximate Computing (AxC) is being actively explored to meet the energy and performance requirements of resource-constrained embedded systems. Approximate arithmetic operators (AxOs), for instance, let edge-AI systems trade tiny, bounded errors for big wins in power, performance, and area. This tutorial demystifies AxO design, modeling, and exploration: from platform-aware operator synthesis (e.g., selective LUT pruning) to application-specific DSE that uses AI/ML to navigate massive trade-off spaces. We contrast selection (library) vs. synthesis (generate-and-optimize) flows, show when FPGA-aware adders/multipliers outperform ASIC-ported designs, and connect operator-level error to task-level metrics (e.g., Conv2D, MLP). The tutorial includes hands-on Jupyter notebooks, ready-to-reuse operator models, and a practical recipe for building Pareto-optimal AxOs under accuracy constraints - plus a peek at AxOSyn, an open-source framework that unifies selection/synthesis, surrogate fitness, and search using evolutionary algorithms. Salim Ullah, Siva Satyendra Sahoo, Akash Kumar 0001 |
CASES | 2 |
| 2025 | Invited Paper: Circuit and Architecture Design with Emerging Computing ParadigmsabstractAs emerging computing paradigms push beyond the limitations of traditional CMOS-based computing using Von Neumann architectures, there is a growing need to rethink and extend Electronic Design Automation (EDA) methodologies to support their unique characteristics. These paradigms—including Approximate Computing, In-Memory Computing, Reconfigurable Field-Effect Transistors (RFETs), and Photonic Computing—represent diverse and promising directions beyond conventional digital design. Collectively, they offer transformative potential for achieving significant improvements in energy efficiency, computational speed, and architectural scalability. For example, application-specific approximate computing enables the design of custom arithmetic circuits that exploit application-level error resilience, allowing for optimized accuracy–power–performance–area (PPA) trade-offs in error-tolerant applications. Similarly, processing-in-non-volatile memories, such as those based on Ferroelectric Field-effect Transistors (FeFETs), enhances energy efficiency by enabling analog computation—particularly for operations like matrix multiplication—directly within the memory arrays. The intrinsic polymorphism of RFETs supports compact, multifunctional logic gates and introduces new opportunities for circuit-level obfuscation and security-aware design. Likewise, photonic analog wavefront computing offers substantial gains in latency and energy efficiency by encoding and processing information in the analog optical domain, leveraging phenomena such as diffraction and interference to perform computation at the speed of light. However, they also introduce a host of new challenges in circuit and architecture design, such as vast and irregular design spaces, analog and non-Boolean behavior, and new device-level constraints that existing EDA tools are not capable of handling. To this end, the current article focuses on the development of efficient and robust EDA frameworks that can enable the practical realization of circuits and architectures in these emerging domains. Salim Ullah, Siva Satyendra Sahoo, Can Li 0024, Chao Li 0065, Liu Liu 0023, Tomas Sousa Pereira, Xunzhao Yin, Armin Darjani, Nima Kavand, Chakravarthy Bodla, Rupa Yashaswi Panduga, Aniruddh Holemadlu, Johannes Maly, Jonathan Förste, Samarth Vadia, Xiaobo Sharon Hu, Akash Kumar 0001 |
ICCAD | 2 |
| 2024 | Enabling Energy-efficient AI Computing: Leveraging Application-specific Approximations : (Education Class)abstractThe widespread adoption of Artificial intelligence and Machine Learning (AI/ML) models across various fields, such as healthcare, autonomous vehicles, smart agriculture, and industrial automation, has led to a growing demand for efficient and scalable AI/ML solutions. However, as AI/ML algorithms grow more complex, their substantial memory requirements and high energy consumption pose significant challenges for deployment on resource-constrained embedded systems, such as wearable health monitors and IoT devices. To this end, various techniques, such as model pruning, knowledge distillation, quantization of model parameters, and employing approximate arithmetic operators, are commonly explored to overcome these challenges [1] . Salim Ullah, Siva Satyendra Sahoo, Akash Kumar 0001 |
CASES | 2 |
| 2024 | AxOSpike: Spiking Neural Networks-Driven Approximate Operator DesignabstractApproximate computing (AxC) is being widely researched as a viable approach to deploying compute-intensive artificial intelligence (AI) applications on resource-constrained embedded systems. In general, AxC aims to provide disproportionate gains in system-level power-performance-area (PPA) by leveraging the implicit error tolerance of an application. One of the more widely used methods in AxC involves circuit pruning of arithmetic operators used to process AI workloads. However, most related works adopt an application-agnostic approach to operator modeling for the design space exploration (DSE) of Approximate Operators (AxOs). To this end, we propose an application-driven approach to designing AxOs. Specifically, we use spiking neural network (SNN)-based inference to present an application-driven operator model resulting in AxOs with better-PPA-accuracy tradeoffs compared to traditional circuit pruning. Additionally, we present a novel FPGA-specific operator model to improve the quality of AxOs that can be obtained using circuit pruning. With the proposed methods, we report designs with up to 26.5% lower PDPxLUTs with similar application-level accuracy. Further, we report a considerably better set of design points than related works with up to 51% better-Pareto front hypervolume. Salim Ullah, Siva Satyendra Sahoo, Akash Kumar 0001 |
IEEE Trans. Comput. Aided Des. Integr. Circuits Syst. | 2 |
| 2024 | AxOCS: Scaling FPGA-Based Approximate Operators Using Configuration SupersamplingabstractThe rising usage of AI/ML-based processing across application domains has exacerbated the need for low-cost ML implementation, specifically for resource-constrained embedded systems. To this end, approximate computing, an approach that explores the power, performance, area (PPA), and behavioral accuracy (BEHAV) trade-offs, has emerged as a possible solution for implementing embedded machine learning. Due to the predominance of MAC operations in ML, designing platform-specific approximate arithmetic operators forms one of the major research problems in approximate computing. Recently, there has been a rising usage of AI/ML-based design space exploration techniques for implementing approximate operators. However, most of these approaches are limited to using ML-based surrogate functions for predicting the PPA and BEHAV impact of a set of related design decisions. While this approach leverages the regression capabilities of ML methods, it does not exploit the more advanced approaches in ML. To this end, we propose, a methodology for designing approximate arithmetic operators through ML-based supersampling. Specifically, we present a method to leverage the correlation of PPA and BEHAV metrics across operators of varying bit-widths for generating larger bit-width operators. The proposed approach involves traversing the relatively smaller design space of smaller bit-width operators and employing its associatedDesign-PPA-BEHAVrelationship to generate initial solutions for metaheuristics-based optimization for larger operators. The experimental evaluation of for FPGA-optimized approximate operators shows that the proposed approach significantly improves the quality—resulting hypervolume for multi-objective optimization—of$8\times8$signed approximate multipliers. Siva Satyendra Sahoo, Salim Ullah, Soumyo Bhattacharjee, Akash Kumar 0001 |
IEEE Trans. Circuits Syst. I Regul. Pap. | 1 |
| 2024 | AxOMaP: Designing FPGA-based Approximate Arithmetic Operators using Mathematical ProgrammingabstractWith the increasing application of machine learning (ML) algorithms in embedded systems, there is a rising necessity to design low-cost computer arithmetic for these resource-constrained systems. As a result, emerging models of computation, such as approximate and stochastic computing, that leverage the inherent error-resilience of such algorithms are being actively explored for implementing ML inference on resource-constrained systems. Approximate computing (AxC) aims to provide disproportionate gains in the power, performance, and area (PPA) of an application by allowing some level of reduction in its behavioral accuracy (BEHAV). Using approximate operators (AxOs) for computer arithmetic forms one of the more prevalent methods of implementing AxC. AxOs provide the additional scope for finer granularity of optimization, compared to only precision scaling of computer arithmetic. To this end, the design of platform-specific and cost-efficient approximate operators forms an important research goal. Recently, multiple works have reported the use of AI/ML-based approaches for synthesizing novel FPGA-based AxOs. However, most of such works limit the use of AI/ML to designing ML-based surrogate functions that are used during iterative optimization processes. To this end, we propose a novel data analysis-driven mathematical programming-based approach to synthesizing approximate operators for FPGAs. Specifically, we formulate mixed integer quadratically constrained programs based on the results of correlation analysis of the characterization data and use the solutions to enable a more directed search approach for evolutionary optimization algorithms. Compared to traditional evolutionary algorithms-based optimization, we report up to 21% improvement in the hypervolume, for joint optimization of PPA and BEHAV, in the design of signed 8-bit multipliers. Further, we report up to 27% better hypervolume than other state-of-the-art approaches to DSE for FPGA-based application-specific AxOs. Siva Satyendra Sahoo, Salim Ullah, Akash Kumar 0001 |
ACM Trans. Reconfigurable Technol. Syst. | 1 |
| 2023 | SyFAxO-GeN: Synthesizing FPGA-Based Approximate Operators with Generative NetworksabstractWith rising trends of moving AI inference to the edge, due to communication and privacy challenges, there has been a growing focus on designing low-cost Edge-AI. Given the diversity of application areas at the edge, FPGA-based systems are increasingly used for high-performance inference. Similarly, approximate computing has emerged as a viable approach to achieve disproportionate resource gains by utilizing the applications' inherent robustness. However, most related research has focused on selecting the appropriate approximate operators for an application from a set of ASIC-based designs. This approach fails to leverage the FPGA's architectural benefits and limits the scope of approximation to already existing generic designs. To this end, we propose an AI-based approach to synthesizing novel approximate operators for FPGA's Look-up-table-based structure. Specifically, we use state-of-the-art generative networks to search for constraint-aware arithmetic operator designs optimized for FPGA-based implementation. With the proposed GANs, we report up to 49% faster training, with negligible accuracy degradation, than related generative networks. Similarly, we report improved hypervolume and increased pareto-front design points compared to state-of-the-art approaches to synthesizing approximate multipliers. Rohit Ranjan, Salim Ullah, Siva Satyendra Sahoo, Akash Kumar 0001 |
ASP-DAC | 3 |
| 2023 | CoOAx: Correlation-aware Synthesis of FPGA-based Approximate OperatorsabstractThe run-time reconfigurability and high parallelism offered by Field Programmable Gate Arrays (FPGAs) make them an attractive choice for implementing hardware accelerators for Machine Learning (ML) algorithms. In the quest for designing efficient FPGA-based hard-ware accelerators for ML algorithms, the inherent error-resilience of ML algorithms can be exploited to implement approximate hard-ware accelerators to trade the output accuracy with better over-all performance. As multiplication and addition are the two main arithmetic operations in ML algorithms, most state-of-the-art approximate accelerators have considered approximate architectures for these operations. However, these works have mainly considered the exploration and selection of approximate operators from an existing set of operators. To this end, we provide an efficient methodology for synthesizing and implementing novel approximate operators. Specifically, we propose a novel operator synthesis approach that supports multiple operator algorithms to provide new approximate multiplier and adder designs for AI inference applications. We report up to 27% and 25% lower power than state-of-the-art approximate designs, with equivalent error behavior, for 8-bit unsigned adders and 4-bit signed multipliers respectively. Further, we propose a correlation-aware Design Space Exploration (DSE) method that can improve the efficacy of randomized search algorithms in synthesizing novel approximate operators. Salim Ullah, Siva Satyendra Sahoo, Akash Kumar 0001 |
ACM Great Lakes Symposium on VLSI | 2 |
| 2023 | AxOTreeS: A Tree Search Approach to Synthesizing FPGA-based Approximate OperatorsabstractApproximate computing (AxC) provides the scope for achieving disproportionate gains in a system’s power, performance, and area (PPA) metrics by leveraging an application’s inherent error-resilient behavior (BEHAV). Trading computational accuracy for performance gains makes AxC an attractive proposition for implementing computationally complex AI/ML-based applications on resource-constrained embedded systems. The growing diversity of application domains using AI/ML has also led to the increasing usage of FPGA-based embedded systems. However, implementing AxC for FPGAs has primarily been limited to the post-processing of ASIC-optimized approximate operators (AxOs). This approach usually involves selecting from a set of AxOs that have been optimized for a gate-based implementation in an ASIC. While such an approach does allow leveraging existing knowledge of ASIC-based AxO design, it limits the scope for considering the challenges and opportunities associated with FPGA’s LUT-based computation structures. Similarly, the few works considering the LUT-based computing for AxO design use generic optimization approaches that do not allow integrating problem-specific prior knowledge—empirical and/or statistical. To this end, we propose a novel tree search-based approach to AxO synthesis for FPGAs. Specifically, we present a design methodology using Monte Carlo Tree Search (MCTS)-based search tree traversal that allows the designer to integrate statistical data, such as correlation, into the AxOs optimization. With the proposed methods, we report improvements over standard MCTS algorithm-based results as well as improved hypervolume for both operator-level and application-specific DSE, compared to state-of-the-art design methodologies. Siva Satyendra Sahoo, Salim Ullah, Akash Kumar 0001 |
ACM Trans. Embed. Comput. Syst. | 1 |
| 2022 | PosAx-O: Exploring Operator-level Approximations for Posit Arithmetic in Embedded AI/MLabstractThe quest for low-cost embedded AI/ML applications has motivated innovations across multiple abstractions of the computation stack. Novel approaches for arithmetic operations have primarily involved quantization, precision-scaling, approximations, and modified data representation. In this context, Posit has emerged as an alternative to the IEEE-754 standard as it offers multiple benefits, primarily due to its dynamic range and tapered precision. However, the implementation of Posit arithmetic operations tends to result in high resource utilization and power dissipation. Consequently, recent works have delved into the idea of exploiting the error resilience of machine learning algorithms by using low-precision Posit arithmetic. However, limiting the exploration to precision-scaling limits the scope for application-specific optimizations for embedded AI/ML applications. To this end, we explore operator-level optimizations and approximations for low-precision Posit numbers. Specifically, we identify and eliminate redundant operations in state-of-the-art Posit arithmetic operator designs and provide a modular framework for exploring approximations in various stages of the computation. We also present a novel framework for behaviorally testing the corresponding Posit approximate designs in Artificial Neural Networks. The proposed optimizations and approximations exhibit considerable resource improvements with a small error in many cases. For instance, a Posit-based multiplier with 1-bit reduced precision shows a 33% improvement in power and utilization, with only a 0.2% degradation in overall accuracy. Amritha Immaneni, Salim Ullah, Suresh Nambi, Siva Satyendra Sahoo, Akash Kumar 0001 |
DSD | 4 |
| 2022 | BOT-MICS: Bounding Time Using Analytics in Mixed-Criticality SystemsabstractAn increasing trend for reducing cost, space, and weight leads to modern embedded systems that execute multiple tasks with different criticality levels on a common hardware platform while guaranteeing a safe operation. In such mixed-criticality (MC) systems, multiple worst case execution times (WCETs) are defined for each task, corresponding to the system operation mode to improve the MC system’s timing behavior at runtime. Determining the appropriate WCETs for lower criticality (LC) modes is nontrivial. On the one hand, considering a very low WCET for tasks can improve the processor utilization by scheduling more tasks in that mode, on the other hand, using a larger WCET ensures that the mode switches (which causes by task overrunning) are minimized, thereby improving the quality of service for all tasks, albeit at the cost of processor utilization. Hitherto, no analytical solutions are proposed to determine WCETs in LC modes. In this regard, we propose a scheme to determine WCETs by the Chebyshev theorem, to make a tradeoff between the number of scheduled tasks at design-time and the number of dropped low-criticality tasks at runtime as a result of frequent mode switches. To have a tight bound of execution times and mode switching probability, we also propose a distribution analytics-based scheme, in which the mode switching probability is obtained based on the cumulative distribution function. Our experimental results show that our scheme improves the utilization of state-of-the-art MC systems by up to 72.27%, while maintaining 24.28% mode switching probability in the worst case scenario. Besides, the results of running embedded real-time benchmarks on a real platform show that the distribution-based scheme can improve the utilization by 7.30% while bounding the mode switching probability by 4.85% more, compared to the Chebyshev-based scheme. Behnaz Ranjbar, Ali Hosseinghorban, Siva Satyendra Sahoo, Alireza Ejlali, Akash Kumar 0001 |
IEEE Trans. Comput. Aided Des. Integr. Circuits Syst. | 3 |
| 2022 | AppAxO: Designing Application-specific Approximate Operators for FPGA-based Embedded SystemsabstractApproximate arithmetic operators, such as adders and multipliers, are increasingly used to satisfy the energy and performance requirements of resource-constrained embedded systems. However, most of the available approximate operators have an application-agnostic design methodology, and the efficacy of these operators can only be evaluated by employing them in the applications. Furthermore, the various available libraries of approximate operators do not share any standard approximation-induction policy to design new operators according to an application’s accuracy and performance constraints. These limitations also hinder the utilization of machine learning models to explore and determine approximate operators according to an application’s requirements. In this work, we present a generic design methodology for implementing FPGA-based application-specific approximate arithmetic operators. Our proposed technique utilizes lookup tables and carry-chains of FPGAs to implement approximate operators according to the input configurations. For instance, for an \( \text{M}\times \text{N} \) accurate multiplier utilizing K lookup tables, our methodology utilizes K -bit configurations to design \( 2^K \) approximate multipliers. We then utilize various machine learning models to evaluate and select configurations satisfying application accuracy and performance constraints. We have evaluated our proposed methodology for three benchmark applications, i.e., biomedical signal processing, image processing, and ANNs. We report more non-dominated approximate multipliers with better hypervolume contribution than state-of-the-art designs for these benchmark applications with the proposed design methodology. Salim Ullah, Siva Satyendra Sahoo, Nemath Ahmed, Debabrata Chaudhury, Akash Kumar 0001 |
ACM Trans. Embed. Comput. Syst. | 2 |
| 2021 | CLAppED: A Design Framework for Implementing Cross-Layer Approximation in FPGA-based Embedded SystemsabstractWith the rising variation and complexity of embedded work-loads, FPGA-based systems are being increasingly used for many applications. The reconfigurability and high parallelism offered by FPGAs are used to enhance the overall performance of these applications. However, the resource constraints of embedded platforms can limit the performance in multiple ways. In recent years, Approximate Computing has emerged as a viable tool for improving the performance by utilizing reduced precision data structures and resource-optimized high-performance arithmetic operators. However, most of the related state-of-the-art research has mainly focused on utilizing approximate computing principles individually on different layers of the computing stack. Nonetheless, approximations across different layers of computing stack can substantially enhance the system’s performance. To this end, we present a framework to enable the intelligent exploration and highly accurate identification of the feasible design points in the large design space enabled by cross-layer approximations. Our framework proposes a novel polynomial regression-based method to model approximate arithmetic operators. The proposed method enables machine learning models to better correlate approximate operators with their impact on an application’s output quality. We use a 2D convolution operator as a test case and present the results for FPGA- based approximate hardware accelerators. Salim Ullah, Siva Satyendra Sahoo, Akash Kumar 0001 |
DAC | 2 |
| 2021 | Improving the Timing Behaviour of Mixed-Criticality Systems Using Chebyshev's TheoremabstractIn Mixed-Criticality (MC) systems, there are often multiple Worst-Case Execution Times (WCETs) for the same task, corresponding to system operation mode. Determining the appropriate WCETs for lower criticality modes is non-trivial; while on the one hand, a low WCET for a mode can improve the processor utilization in that mode, on the other hand, using a larger WCET ensures that the mode switches are minimized, thereby maximizing the quality-of-service for all tasks, albeit at the cost of processor utilization. Although there are many studies to determine WCET in the highest criticality mode, no analytical solutions are proposed to determine WCETs in other lower criticality modes. In this regard, we propose a scheme to determine WCETs by Chebyshev theorem to make a trade-off between the number of scheduled tasks at design-time and the number of dropped low-criticality tasks at runtime as a result of frequent mode switches. Our experimental results show that our scheme improves the utilization of state-of-the-art MC systems by up to 85.29%, while maintaining 9.11% mode switching probability in the worst-case scenario. Behnaz Ranjbar, Ali Hoseinghorban, Siva Satyendra Sahoo, Alireza Ejlali, Akash Kumar 0001 |
DATE | 3 |
| 2021 | MemOReL: A Memory-oriented Optimization Approach to Reinforcement Learning on FPGA-based Embedded SystemsabstractReinforcement Learning (RL) represents the machine learning method that has come closest to showing human-like learning. While Deep RL is becoming increasingly popular for complex applications such as AI-based gaming, it has a high implementation cost in terms of both power and latency. Q-Learning, on the other hand, is a much simpler method that makes it more feasible for implementation on resource-constrained embedded systems for control and navigation. However, the optimal policy search in Q-Learning is a compute-intensive and inherently sequential process and a software-only implementation may not be able to satisfy the latency and throughput constraints of such applications. To this end, we propose a novel accelerator design with multiple design trade-offs for implementing Q-Learning on FPGA-based SoCs. Specifically, we analyze the various stages of the Epsilon-Greedy algorithm for RL and propose a novel microarchitecture that reduces the latency by optimizing the memory access during each iteration. Consequently, we present multiple designs that provide varying trade-offs between performance, power dissipation, and resource utilization of the accelerator. With the proposed approach, we report considerable improvement in throughput with lower resource utilization over state-of-the-art design implementations. Siva Satyendra Sahoo, Akhil Raj Baranwal, Salim Ullah, Akash Kumar 0001 |
ACM Great Lakes Symposium on VLSI | 1 |
| 2021 | CLEO-CoDe: Exploiting Constrained Decoding for Cross-Layer Energy Optimization in Heterogeneous Embedded SystemsabstractSystem-level design for low-power and energy efficiency in embedded systems using Heterogeneous Multi-Processor System-on-Chip (HMPSoC) is a challenging task due to the large design space. The related Design Space Exploration (DSE) suffers from scaling due to various degrees of freedom across multiple layers of the compute stack. Traditional multi-objective metaheuristic approaches work well for unconstrained system-level design, but do not scale well with the additional system and user constraints. Using a SATisfiablity problem (SAT) solver as a decoder for the meta-heuristics has been explored in related research as a better solution for a discrete constrained multi-objective optimization problem. This approach restricts the problem to the feasible space, hence improving the quality of the results. In this paper, we explore the ways in which constrained decoding such as the SAT decoding approach can be leveraged for cross-layer design space exploration. Low-power methodologies such as Dynamic Voltage and Frequncy Scaling (DVFS) and application-specific implementations are integrated, thus scaling the design space. Additionally, we demonstrate how user constraints on the system synthesis problem can be learned by our proposed approach to prune the meta-heuristic design space and improve the quality of the solutions. As the constraints on the problem increase and the design space scales, the constrained decoding approach outperforms a typical meta-heuristic approach. Siva Satyendra Sahoo, Akash Kumar 0001 |
VLSI-SoC | 1 |
| 2021 | Using Monte Carlo Tree Search for EDA - A Case-study with Designing Cross-layer Reliability for Heterogeneous Embedded SystemsabstractContinued transistor scaling and increasing power density have led to considerable increase in fault-rates in silicon nanotechnology-based real-time systems. Cross-layer fault tolerance techniques present a more cost-efficient methodology for adapting to such increased fault rates by distributing fault-tolerance to different layers. To this end, we propose a methodology for integrating the design space exploration (DSE) for taskmapping on heterogeneous hardware-platforms with designing cross-layer reliability. Specifically, we model the DSE for task-mapping with cross-layer reliability as a tree search problem and use Monte Carlo Tree Search for task-mapping and scheduling applications with specific reliability requirements. The proposed methodology results in considerable improvements over a standalone approach to task-mapping and implementing cross-layer reliability. Siva Satyendra Sahoo, Akash Kumar 0001 |
VLSI-SoC | 1 |
| 2021 | Area-Optimized Accurate and Approximate Softcore Signed Multiplier ArchitecturesabstractMultiplication is one of the most extensively used arithmetic operations in a wide range of applications. In order to provide resource-efficient and high-performance multipliers, previous works have proposed different designs of accurate and approximate multipliers-mainly for ASIC-based systems. However, the architectural differences between ASICs- and FPGA-based systems limit the effectiveness of these multipliers for FPGA-based systems. Moreover, most of these multiplier designs are valid only for unsigned numbers. To bridge this gap, we propose a novel implementation technique for designing resource-efficient and low-power accurate and approximate signed multipliers which are optimized for FPGA-based systems. Compared to Vivado's area-optimized multiplier IPs, the designs obtained using our proposed technique occupy 47 to 63 percent less area (Lookup Tables). To accelerate further research in this direction and reproduce the presented results, the RTL and behavioral models of our proposed methodology are available as an open-source library.11.Online. [Available]: https://cfaed.tu-dresden.de/pd-downloads. Salim Ullah, Hendrik Schmidl, Siva Satyendra Sahoo, Semeen Rehman, Akash Kumar 0001 |
IEEE Trans. Computers | 3 |
| 2021 | ReLAccS: A Multilevel Approach to Accelerator Design for Reinforcement Learning on FPGA-Based SystemsabstractReinforcement learning (RL), specifically Q-learning, with human-like learning abilities to learn from experience without any a priori data, is being increasingly used in embedded systems in the field of control and navigation. However, finding the optimal policy in this approach can be highly compute-intensive, and a software-only implementation may not satisfy the application's timing constraints. To this end, we propose optimization methods at multiple levels of accelerator design for RL. Specifically, at the architecture-level, we exploit the instruction-level parallelism and the spatial parallelism in FPGAs to improve the throughput over state-of-the-art designs by up to 34%. Further, we propose lookup table-level optimizations to reduce the resource utilization and power dissipation of the accelerator. Finally, we propose algorithm-level approximation that can be used for acceleration of Q-learning problems with more states and for reducing the peak power dissipation. We report up to 10× reduction in power dissipation with marginal degradation in quality of results. Akhil Raj Baranwal, Salim Ullah, Siva Satyendra Sahoo, Akash Kumar 0001 |
IEEE Trans. Comput. Aided Des. Integr. Circuits Syst. | 3 |
| 2020 | CL(R)Early: An Early-stage DSE Methodology for Cross-Layer Reliability-aware Heterogeneous Embedded SystemsabstractCross-layer reliability (CLR) presents a cost-effective alternative to traditional single-layer design in resource-constrained embedded systems. CLR provides the scope for leveraging the inherent fault-masking of multiple layers and exploiting application-specific tolerances to degradation in some Quality of Service (QoS) metrics. However, it can also lead to an explosion in the design complexity. State-of-the art approaches to such joint optimization across multiple degrees of freedom can lead to degradation in the system-level Design Space Exploration (DSE) results. To this end, we propose a DSE methodology for enabling CLR-aware task-mapping in heterogeneous embedded systems. Specifically, we present novel approaches to both task and system-level analysis for performing an early-stage exploration of various design decisions. The proposed methodology results in considerable improvements over other state-of-the-art approaches and shows significant scaling with application size. Siva Satyendra Sahoo, Bharadwaj Veeravalli, Akash Kumar 0001 |
DAC | 1 |
| 2020 | DiSCERN: Distilling Standard-Cells for Emerging Reconfigurable NanotechnologiesabstractRecent attempts on circuits based on emerging reconfigurable nanotechnologies have primarily focused on using the traditional CMOS design flow involving similar-styled standard-cells. In the present work, we show that logic gates which implement self-dual functions can be efficiently implemented using reconfigurable nanotechnologies. We propose an algorithm which analyses the truth-tables of cuts in a mapped circuit to list all such potential reconfigurable logic gates for a particular circuit. Technology mapping with these new logic gates (or standard-cells) leads to a better mapping in terms of area and delay. Experiments employing our methodology over EPFL benchmarks, show average improvements of around 13%, 16% and 11.5% in terms of area, number of edges and delay respectively as compared to the conventional CMOS-centric standard-cell based mapping. Shubham Rai, Michael Raitza, Siva Satyendra Sahoo, Akash Kumar 0001 |
DATE | 3 |
| 2019 | A Hybrid Agent-based Design Methodology for Dynamic Cross-layer Reliability in Heterogeneous Embedded SystemsabstractTechnology scaling and architectural innovations have led to increasing ubiquity of embedded systems across applications with widely varying and often constantly changing performance and reliability specifications. However, the increasing physical fault-rates in electronic systems have led to single-layer reliability approaches becoming infeasible for resource-constrained systems. Dynamic Cross-layer reliability (CLR) provides scope for efficient adaptation to such QoS variations and increasing unreliability. We propose a design methodology for enabling QoS-aware CLR-integrated runtime adaptation in heterogeneous MPSoC-based embedded systems. Specifically, we propose a combination of reconfiguration cost-aware optimization at design-time and an agent-based optimization at run-time. We report a reduction of up to 51% and 37% in average reconfiguration cost and average energy consumption respectively over state-of-the-art approaches. Siva Satyendra Sahoo, Bharadwaj Veeravalli, Akash Kumar 0001 |
DAC | 1 |
| 2019 | Multi-objective design space exploration for system partitioning of FPGA-based Dynamic Partially Reconfigurable Systems
Siva Satyendra Sahoo, Tuan D. A. Nguyen, Bharadwaj Veeravalli, Akash Kumar 0001 |
Integr. | 1 |
| 2018 | Lifetime-aware design methodology for dynamic partially reconfigurable systemsabstractDynamic Partial Reconfiguration (DPR) in reconfigurable platforms can be used for the mitigation of aging-related permanent faults. We propose an application-specific system-level design methodology for determining the appropriate number of Partially Reconfigurable Regions and their compatibility with Partially Reconfigurable Modules for maximizing the system lifetime. Specifically, we propose a lifetime-aware scheduler that maximizes system MTTF. We use the scheduler along with an automated floorplanner for design space exploration at design-time to generate a heterogeneous PRR system. Our experiments show that the heterogeneous systems can offer up to 2x lifetime improvement over homogeneous ones. Siva Satyendra Sahoo, Tuan D. A. Nguyen, Bharadwaj Veeravalli, Akash Kumar 0001 |
ASP-DAC | 1 |
| 2018 | QoS-Aware Cross-Layer Reliability-Integrated FPGA-Based Dynamic Partially Reconfigurable System PartitioningabstractDynamic Partial Reconfiguration (DPR) can be used for time-sharing of computing resources within Partially Reconfigurable Regions (PRRs) in FPGA-based systems. The heterogeneous partitioning in such systems allows the user to exploit the application-specific mapping of Partially Reconfigurable Modules (PRMs) to PRRs to implement more efficient designs. It offers increased opportunities in optimizing the reliability of the system across multiple layers - from the low-level physical one to the higher application layer. This method, called cross-layer reliability, can potentially exploit the application-specific tolerances to the quality of service (QoS) to tackle the increasing device fault-rates more cost-effectively by distributing the fault-mitigation to different layers. In this work, we propose a QoS-aware cross-layer reliability-integrated design methodology for FPGA-based DPR systems. Specifically, our methodology analyzes the requirements of the applications in terms of Functional Reliability, System Lifetime and Makespan to determine the best possible combinations of reliability-oriented design choices in different layers. We report up to an average of 24% and 30% performance improvements for single and multi-objective optimization-based system partitioning. Siva Satyendra Sahoo, Tuan D. A. Nguyen, Bharadwaj Veeravalli, Akash Kumar 0001 |
FPT | 1 |
| 2016 | Design and evaluation of reliability-oriented task re-mapping in MPSoCs using time-series analysis of intermittent faults
Siva Satyendra Sahoo, Akash Kumar 0001, Bharadwaj Veeravalli |
DATE | 1 |