33 research outputs found
Energy-Efficient Inference Accelerator for Memory-Augmented Neural Networks on an FPGA
Memory-augmented neural networks (MANNs) are designed for question-answering
tasks. It is difficult to run a MANN effectively on accelerators designed for
other neural networks (NNs), in particular on mobile devices, because MANNs
require recurrent data paths and various types of operations related to
external memory access. We implement an accelerator for MANNs on a
field-programmable gate array (FPGA) based on a data flow architecture.
Inference times are also reduced by inference thresholding, which is a
data-based maximum inner-product search specialized for natural language tasks.
Measurements on the bAbI data show that the energy efficiency of the
accelerator (FLOPS/kJ) was higher than that of an NVIDIA TITAN V GPU by a
factor of about 125, increasing to 140 with inference thresholdingComment: Accepted to DATE 201
Spiking-YOLO: Spiking Neural Network for Energy-Efficient Object Detection
Over the past decade, deep neural networks (DNNs) have demonstrated
remarkable performance in a variety of applications. As we try to solve more
advanced problems, increasing demands for computing and power resources has
become inevitable. Spiking neural networks (SNNs) have attracted widespread
interest as the third-generation of neural networks due to their event-driven
and low-powered nature. SNNs, however, are difficult to train, mainly owing to
their complex dynamics of neurons and non-differentiable spike operations.
Furthermore, their applications have been limited to relatively simple tasks
such as image classification. In this study, we investigate the performance
degradation of SNNs in a more challenging regression problem (i.e., object
detection). Through our in-depth analysis, we introduce two novel methods:
channel-wise normalization and signed neuron with imbalanced threshold, both of
which provide fast and accurate information transmission for deep SNNs.
Consequently, we present a first spiked-based object detection model, called
Spiking-YOLO. Our experiments show that Spiking-YOLO achieves remarkable
results that are comparable (up to 98%) to those of Tiny YOLO on non-trivial
datasets, PASCAL VOC and MS COCO. Furthermore, Spiking-YOLO on a neuromorphic
chip consumes approximately 280 times less energy than Tiny YOLO and converges
2.3 to 4 times faster than previous SNN conversion methods.Comment: Accepted to AAAI 202
SimFLE: Simple Facial Landmark Encoding for Self-Supervised Facial Expression Recognition in the Wild
One of the key issues in facial expression recognition in the wild (FER-W) is
that curating large-scale labeled facial images is challenging due to the
inherent complexity and ambiguity of facial images. Therefore, in this paper,
we propose a self-supervised simple facial landmark encoding (SimFLE) method
that can learn effective encoding of facial landmarks, which are important
features for improving the performance of FER-W, without expensive labels.
Specifically, we introduce novel FaceMAE module for this purpose. FaceMAE
reconstructs masked facial images with elaborately designed semantic masking.
Unlike previous random masking, semantic masking is conducted based on channel
information processed in the backbone, so rich semantics of channels can be
explored. Additionally, the semantic masking process is fully trainable,
enabling FaceMAE to guide the backbone to learn spatial details and contextual
properties of fine-grained facial landmarks. Experimental results on several
FER-W benchmarks prove that the proposed SimFLE is superior in facial landmark
localization and noticeably improved performance compared to the supervised
baseline and other self-supervised methods
Fast and Efficient Information Transmission with Burst Spikes in Deep Spiking Neural Networks
The spiking neural networks (SNNs) are considered as one of the most
promising artificial neural networks due to their energy efficient computing
capability. Recently, conversion of a trained deep neural network to an SNN has
improved the accuracy of deep SNNs. However, most of the previous studies have
not achieved satisfactory results in terms of inference speed and energy
efficiency. In this paper, we propose a fast and energy-efficient information
transmission method with burst spikes and hybrid neural coding scheme in deep
SNNs. Our experimental results showed the proposed methods can improve
inference energy efficiency and shorten the latency.Comment: Accepted to DAC 201
Energy-efficient Knowledge Distillation for Spiking Neural Networks
Spiking neural networks (SNNs) have been gaining interest as energy-efficient
alternatives of conventional artificial neural networks (ANNs) due to their
event-driven computation. Considering the future deployment of SNN models to
constrained neuromorphic devices, many studies have applied techniques
originally used for ANN model compression, such as network quantization,
pruning, and knowledge distillation, to SNNs. Among them, existing works on
knowledge distillation reported accuracy improvements of student SNN model.
However, analysis on energy efficiency, which is also an important feature of
SNN, was absent. In this paper, we thoroughly analyze the performance of the
distilled SNN model in terms of accuracy and energy efficiency. In the process,
we observe a substantial increase in the number of spikes, leading to energy
inefficiency, when using the conventional knowledge distillation methods. Based
on this analysis, to achieve energy efficiency, we propose a novel knowledge
distillation method with heterogeneous temperature parameters. We evaluate our
method on two different datasets and show that the resulting SNN student
satisfies both accuracy improvement and reduction of the number of spikes. On
MNIST dataset, our proposed student SNN achieves up to 0.09% higher accuracy
and produces 65% less spikes compared to the student SNN trained with
conventional knowledge distillation method. We also compare the results with
other SNN compression techniques and training methods
Removal of Alpha-Gal Epitopes from Porcine Aortic Valve and Pericardium using Recombinant Human Alpha Galactosidase A
It has been reported that the immune response due to α-Gal epitopes is an important factor in tissue valve failure. The elimination of the interaction between the natural anti-Gal antibodies and α-gal epitopes on the xenografts is a prerequisite to the success of xenografts in humans. Previously, we reported that the green coffee bean α-galactosidase could remove all α-Gal epitopes from cell surface of porcine aortic valve and pericardial tissue, but it has limitations on cost effectiveness. In this study we wanted to know whether the recently produced recombinant human α-galactosidase A has the same effective enzymatic activity as green coffee bean α-galactosidase in removing α-Gal epitopes from the same tissues. After treating fresh porcine aortic valve and pericardial tissue with recombinant α-galactosidase A, each sample was stained with Griffonia simplicifolia type I isolectin B4 indirect immunoperoxidase avidin-biotin technique. We then examined whether the α-Gal epitopes were reduced or abolished in each consecutive concentration of recombinant α-galactosidase A by comparing the degree of the Griffonia simplicifolia isolectin B4 staining. As a result, the recombinant α-galactosidase A could remove cell surface α-Gals on porcine aortic valve and pericardial tissue as effectively as green coffee bean α-galactosidase
Surgical Treatment of Native Valve Aspergillus Endocarditis and Fungemic Vascular Complications
Systemic infection with Aspergillus is an opportunistic disease that affects mainly immunocompromised hosts, and is associated with a high mortality rate. It typically occurs in patients with several predisposing factors, but Aspergillus endocarditis of native valves is rare and experience in diagnosis and treatment is limited. We report a case of native valve endocarditis caused by Aspergillus. A 35-yr-old male patient who underwent pericardiocentesis four months previously for pericardial effusion of unknown etiology presented with right leg pain and absence of the right femoral artery pulse. Cardiac echocardiography revealed severe mitral insufficiency with large mobile vegetations, and computed tomographic angiography showed embolic occlusion of both common iliac arteries. We performed mitral valve replacement and thromoembolectomy, and Aspergillus was identified as the vegetation. We started intravenous amphotericin B and oral itraconazole, but systemic complications developed including superior mesenteric artery aneurysm and gastrointestinal bleeding. After aggressive management, the patient was discharged 78 days post surgery on oral itraconazole. He was well at 12 months post discharge but died in a traffic accident 13 months after discharge
Dual Pointer Network for Fast Extraction of Multiple Relations in a Sentence
Relation extraction is a type of information extraction task that recognizes semantic relationships between entities in a sentence. Many previous studies have focused on extracting only one semantic relation between two entities in a single sentence. However, multiple entities in a sentence are associated through various relations. To address this issue, we proposed a relation extraction model based on a dual pointer network with a multi-head attention mechanism. The proposed model finds n-to-1 subject–object relations using a forward object decoder. Then, it finds 1-to-n subject–object relations using a backward subject decoder. Our experiments confirmed that the proposed model outperformed previous models, with an F1-score of 80.8% for the ACE (automatic content extraction) 2005 corpus and an F1-score of 78.3% for the NYT (New York Times) corpus