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Abstract-A preliminary study by Sneddon et al. (2005) using visual working memory tasks coupled with quantified EEG (qEEG) analysis distinguished mild dementia subjects from normal aging ones with a high degree of accuracy. The present study hypothesizes that a simpler task such as having a subject count backwards mentally by ones can be coupled with qEEG to yield a similar degree of accuracy for classifying early dementia. The study focuses on participants with mild cognitive impairment (MCI) and includes both a delayed visual match-tosample (working memory) task and a counting backwards task (eyes closed) for comparison. The counting backwards protocol included 15 normal aging and 11 MCI participants, and the working memory task included 9 normal aging and 7 MCI individuals. The EEG data were quantified using Tsallis entropy, and the brain regions analyzed included the prefrontal cortex, occipital lobe, and the posterior parietal cortex. The

In this paper we give a fresh look to Coarse Grained Reconfigurable Arrays (CGRAs) as ultra-low power accelerators for near-sensor processing. We present a general-purpose Integrated Programmable-Array accelerator (IPA) exploiting a novel architecture, execution model, and compilation flow for application mapping that can handle kernels containing complex control flow, without the significant energy overhead incurred by state of the art predication approaches. To optimize the performance and energy efficiency, we explore the IPA architecture with special focus on shared memory access, with the help of the flexible compilation flow presented in this paper. We achieve a maximum energy gain of 2×, and performance gain of 1.33× and 1.8× compared with state of the art partial and full predication techniques, respectively. The proposed accelerator achieves an average energy efficiency of 1617 MOPS/mW operating at 100MHz, 0.6V in 28nm UTBB FD-SOI technology, over a wide range of near-sensor processing kernels, leading to an improvement up to 18×, with an average of 9.23× (as well as a speed-up up to 20.3×, with an average of 9.7×) compared to a core specialized for ultra-low power near-sensor processing.

Coarse-Grained Reconfigurable Architectures (CGRAs) are promising high-performance and power-efficient platforms. However, their uses are still limited because of the current capability of the mapping tools. This paper presents a new scalable efficient design flow to map applications written in high level language on CGRAs. This approach leverages on simultaneous scheduling and binding steps respectively based on a heuristic and an exact method stochastically degenerated. The formal graph model of the application, obtained after compilation, is backward traversed and dynamically transformed when needed to allow for a better exploration of the design space. Results show that our approach is scalable, finds most of the time the best solutions i.e. the mappings with the shortest latencies, achieves lowest failure rate in carrying out solutions, provides lower computation time and explores more efficiently the solution space than the state of the art methods.

In recent years, Coarse Grain Reconfigurable Architecture (CGRA) accelerators have been increasingly deployed in Internet-of-Things (IoT) end nodes. A modern CGRA has to support and efficiently accelerate both integer and floating-point (FP) operations. In this paper, we propose an ultra-low-power tunableprecision CGRA architectural template, called TRANSprecision floating-point Programmable archItectuRE (TRANSPIRE), and its associated compilation flow supporting both integer and FP operations. TRANSPIRE employs transprecision computing and multiple Single Instruction Multiple Data (SIMD) to accelerate FP operations while boosting energy efficiency as well. Experimental results show that TRANSPIRE achieves a maximum of 10.06× performance gain and consumes 12.91× less energy w.r.t. a RISC-V based CPU with an enhanced ISA supporting SIMD-style vectorization and FP data-types, while executing applications for near-sensor computing and embedded machine learning, with an area overhead of 1.25× only.

In the approaching era of IoT, flexible and low power accelerators have become essential to meet aggressive energy efficiency targets. During the last few decades, Coarse Grain Reconfigurable Arrays (CGRA) have demonstrated high energy efficiency as accelerators, especially for high-performance streaming applications. While existing CGRAs mostly rely on partial and full predication techniques to support conditional branches, inefficient architecture and mapping support for handling control flow limits the use of CGRAs in accelerating either only inner loop bodies, or transformed loops specifically adapted to the target CGRA. This paper proposes a novel CGRA architecture with support for jump and conditional jump instructions and a lightweight global synchronization mechanism to enable complete Control Data Flow Graph (CDFG) mapping in an ultra-lowpower environment. The architecture is coupled with a complete design flow that efficiently maps applications with heavy control flow starting from a generic C language description. The proposed mapping approach reduces the impact of wasteful instruction issues in the conventional approaches of predication providing an average energy improvement of 1.44x and 1.6x when compared to the state of the art partial and full predication techniques. Moreover, the proposed method achieves an average speed-up up to 21x and an energy improvement up to 50.42x while executing applications with heavy control flow with respect to sequential execution on a low-power embedded CPU, demonstrating its suitability for next generation IoT applications.

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Due to increasing demand of low power computing, and diminishing returns from technology scaling, industry and academia are turning with renewed interest toward energyefficient programmable accelerators. This paper proposes an Integrated Programmable-Array accelerator (IPA) architecture based on an innovative execution model, targeted to accelerate both data and control-flow parts of deeply embedded vision applications typical of edge-nodes of the Internet of Things (IoT). In this paper we demonstrate the performance and energy efficiency of IPA implementing a smart visual trigger application. Experimental results show that the proposed accelerator delivers 507 MOPS and 142 MOPS/mW on the target application, surpassing a low-power processor optimized for DSP applications by 6x in performance and by 10x in energy efficiency. Moreover, it surpasses performance of state of the art CGRAs only capable of implementing data-flow portion of applications by 1.6x, demonstrating the effectiveness of the proposed architecture and computational model.