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In this paper, we propose IMA-GNN as an In-Memory Accelerator for centralized and decentralized Graph Neural Network inference, explore its potential in both settings and provide a guideline for the community targeting flexible and efficient edge computation. Leveraging IMA-GNN, we first model the computation and communication latencies of edge devices. We then present practical case studies on GNN-based taxi demand and supply prediction and also adopt four large graph datasets to quantitatively compare and analyze centralized and decentralized settings. Our cross-layer simulation results demonstrate that on average, IMA-GNN in the centralized setting can obtain ~790x communication speed-up compared to the decentralized GNN setting. However, the decentralized setting performs computation ~1400x faster while reducing the power consumption per device. This further underlines the need for a hybrid semi-decentralized GNN approach. 

Recently, Intelligent IoT (IIoT), including various sensors, has gained significant attention due to its capability of sensing, deciding, and acting by leveraging artificial neural networks (ANN). Nevertheless, to achieve acceptable accuracy and high performance in visual systems, a power-delay-efficient architecture is required. In this paper, we propose an ultra-low-power processing in-sensor architecture, namely SenTer, realizing low-precision ternary multi-layer perceptron networks, which can operate in detection and classification modes. Moreover, SenTer supports two activation functions based on user needs and the desired accuracy-energy trade-off. SenTer is capable of performing all the required computations for the MLP's first layer in the analog domain and then submitting its results to a co-processor. Therefore, SenTer significantly reduces the overhead of analog buffers, data conversion, and transmission power consumption by using only one ADC. Additionally, our simulation results demonstrate acceptable accuracy on various datasets compared to the full precision models. 

Deep Neural Network (DNN) acceleration with digital Processing-in-Memory (PIM) platforms at the edge is an actively-explored domain with great potential to not only address memory-wall bottlenecks but to offer orders of performance improvement in comparison to the von-Neumann architecture. On the other side, FPGA-based edge computing has been followed as a potential solution to accelerate compute-intensive workloads. In this work, adopting low-bit-width neural networks, we perform a solid and comparative inference performance analysis of a recent processing-in-SRAM tape-out with a low-resource FPGA board and a high-performance GPU to provide a guideline for the research community. We explore and highlight the key architectural constraints of these edge candidates that impact their overall performance. Our experimental data demonstrate that the processing-in-SRAM can obtain up to ~160x speed-up and up to 228x higher efficiency (img/s/W) compared to the under-test FPGA on the CIFAR-10 dataset. 

In this work, we leverage the uni-polar switching behavior of Spin-Orbit Torque Magnetic Random Access Memory (SOT-MRAM) to develop an efficient digital Computing-in-Memory (CiM) platform named XOR-CiM. XOR-CiM converts typical MRAM sub-arrays to massively parallel computational cores with ultra-high bandwidth, greatly reducing energy consumption dealing with convolutional layers and accelerating X(N)OR-intensive Binary Neural Networks (BNNs) inference. With a similar inference accuracy to digital CiMs, XOR-CiM achieves ∼4.5× and 1.8× higher energy-efficiency and speed-up compared to the recent MRAM-based CiM platforms. 

In this work, we propose a Parallel Processing-In-DRAM architecture named P-PIM leveraging the high density of DRAM to enable fast and flexible computation. P-PIM enables bulk bit-wise in-DRAM logic between operands in the same bit-line by elevating the analog operation of the memory sub-array based on a novel dual-row activation mechanism. With this, P-PIM can opportunistically perform a complete and inexpensive in-DRAM RowHammer (RH) self-tracking and mitigation technique to protect the memory unit against such a challenging security vulnerability. Our results show that P-PIM achieves ~72% higher energy efficiency than the fastest charge-sharing-based designs. As for the RH protection, with a worst-case slowdown of ~0.8%, P-PIM archives up to 71% energy-saving over the SRAM/CAM-based frameworks and about 90% saving over DRAM-based frameworks. 

In this work, a high-speed and energy-efficient comparator-based N ear- S ensor L ocal B inary P attern accelerator architecture (NS-LBP) is proposed to execute a novel local binary pattern deep neural network. First, inspired by recent LBP networks, we design an approximate, hardware-oriented, and multiply-accumulate (MAC)-free network named Ap-LBP for efficient feature extraction, further reducing the computation complexity. Then, we develop NS-LBP as a processing-in-SRAM unit and a parallel in-memory LBP algorithm to process images near the sensor in a cache, remarkably reducing the power consumption of data transmission to an off-chip processor. Our circuit-to-application co-simulation results on MNIST and SVHN datasets demonstrate minor accuracy degradation compared to baseline CNN and LBP-network models, while NS-LBP achieves 1.25 GHz and an energy-efficiency of 37.4 TOPS/W. NS-LBP reduces energy consumption by 2.2× and execution time by a factor of 4× compared to the best recent LBP-based networks.