51 research outputs found
Forward and Backward Information Retention for Accurate Binary Neural Networks
Weight and activation binarization is an effective approach to deep neural
network compression and can accelerate the inference by leveraging bitwise
operations. Although many binarization methods have improved the accuracy of
the model by minimizing the quantization error in forward propagation, there
remains a noticeable performance gap between the binarized model and the
full-precision one. Our empirical study indicates that the quantization brings
information loss in both forward and backward propagation, which is the
bottleneck of training accurate binary neural networks. To address these
issues, we propose an Information Retention Network (IR-Net) to retain the
information that consists in the forward activations and backward gradients.
IR-Net mainly relies on two technical contributions: (1) Libra Parameter
Binarization (Libra-PB): simultaneously minimizing both quantization error and
information loss of parameters by balanced and standardized weights in forward
propagation; (2) Error Decay Estimator (EDE): minimizing the information loss
of gradients by gradually approximating the sign function in backward
propagation, jointly considering the updating ability and accurate gradients.
We are the first to investigate both forward and backward processes of binary
networks from the unified information perspective, which provides new insight
into the mechanism of network binarization. Comprehensive experiments with
various network structures on CIFAR-10 and ImageNet datasets manifest that the
proposed IR-Net can consistently outperform state-of-the-art quantization
methods
OHQ: On-chip Hardware-aware Quantization
Quantization emerges as one of the most promising approaches for deploying
advanced deep models on resource-constrained hardware. Mixed-precision
quantization leverages multiple bit-width architectures to unleash the accuracy
and efficiency potential of quantized models. However, existing mixed-precision
quantization suffers exhaustive search space that causes immense computational
overhead. The quantization process thus relies on separate high-performance
devices rather than locally, which also leads to a significant gap between the
considered hardware metrics and the real deployment.In this paper, we propose
an On-chip Hardware-aware Quantization (OHQ) framework that performs
hardware-aware mixed-precision quantization without accessing online devices.
First, we construct the On-chip Quantization Awareness (OQA) pipeline, enabling
perceive the actual efficiency metrics of the quantization operator on the
hardware.Second, we propose Mask-guided Quantization Estimation (MQE) technique
to efficiently estimate the accuracy metrics of operators under the constraints
of on-chip-level computing power.By synthesizing network and hardware insights
through linear programming, we obtain optimized bit-width configurations.
Notably, the quantization process occurs on-chip entirely without any
additional computing devices and data access. We demonstrate accelerated
inference after quantization for various architectures and compression ratios,
achieving 70% and 73% accuracy for ResNet-18 and MobileNetV3, respectively. OHQ
improves latency by 15~30% compared to INT8 on deployment.Comment: 10 pages, 6 figure
Strained hybrid perovskite thin films and their impact on the intrinsic stability of perovskite solar cells
Organic-inorganic hybrid perovskite (OIHP) solar cells have achieved comparable efficiencies to those of commercial solar cells, although their instability hinders their commercialization. Although encapsulation techniques have been developed to protect OIHP solar cells from external stimuli such as moisture, oxygen, and ultraviolet light, understanding of the origin of the intrinsic instability of perovskite films is needed to improve their stability. We show that the OIHP films fabricated by existing methods are strained and that strain is caused by mismatched thermal expansion of perovskite films and substrates during the thermal annealing process. The polycrystalline films have compressive strain in the out-of-plane direction and in-plane tensile strain. The strain accelerates degradation of perovskite films under illumination, which can be explained by increased ion migration in strained OIHP films. This study points out an avenue to enhance the intrinsic stability of perovskite films and solar cells by reducing residual strain in perovskite films
Strained hybrid perovskite thin films and their impact on the intrinsic stability of perovskite solar cells
Organic-inorganic hybrid perovskite (OIHP) solar cells have achieved comparable efficiencies to those of commercial solar cells, although their instability hinders their commercialization. Although encapsulation techniques have been developed to protect OIHP solar cells from external stimuli such as moisture, oxygen, and ultraviolet light, understanding of the origin of the intrinsic instability of perovskite films is needed to improve their stability. We show that the OIHP films fabricated by existing methods are strained and that strain is caused by mismatched thermal expansion of perovskite films and substrates during the thermal annealing process. The polycrystalline films have compressive strain in the out-of-plane direction and in-plane tensile strain. The strain accelerates degradation of perovskite films under illumination, which can be explained by increased ion migration in strained OIHP films. This study points out an avenue to enhance the intrinsic stability of perovskite films and solar cells by reducing residual strain in perovskite films
Strained hybrid perovskite thin films and their impact on the intrinsic stability of perovskite solar cells
Organic-inorganic hybrid perovskite (OIHP) solar cells have achieved comparable efficiencies to those of commercial solar cells, although their instability hinders their commercialization. Although encapsulation techniques have been developed to protect OIHP solar cells from external stimuli such as moisture, oxygen, and ultraviolet light, understanding of the origin of the intrinsic instability of perovskite films is needed to improve their stability. We show that the OIHP films fabricated by existing methods are strained and that strain is caused by mismatched thermal expansion of perovskite films and substrates during the thermal annealing process. The polycrystalline films have compressive strain in the out-of-plane direction and in-plane tensile strain. The strain accelerates degradation of perovskite films under illumination, which can be explained by increased ion migration in strained OIHP films. This study points out an avenue to enhance the intrinsic stability of perovskite films and solar cells by reducing residual strain in perovskite films
Identification and Characterization of the Anti-Methicillin-Resistant \u3ci\u3eStaphylococcus aureus\u3c/i\u3e WAP-8294A2 Biosynthetic Gene Cluster from \u3ci\u3eLysobacter enzymogenes\u3c/i\u3e OH11
Lysobactor enzymogenes strain OH11 is an emerging biological control agent of fungal and bacterial diseases. We recently completed its genome sequence and found it contains a large number of gene clusters putatively responsible for the biosynthesis of nonribosomal peptides and polyketides, including the previously identified antifungal dihydromaltophilin (HSAF). One of the gene clusters contains two huge open reading frames, together encoding 12 modules of nonribosomal peptide synthetases (NRPS). Gene disruption of one of the NRPS led to the disappearance of a metabolite produced in the wild type and the elimination of its antibacterial activity. The metabolite and antibacterial activity were also affected by the disruption of some of the flanking genes. We subsequently isolated this metabolite and subjected it to spectroscopic analysis. The mass spectrometry and nuclear magnetic resonance data showed that its chemical structure is identical to WAP-8294A2, a cyclic lipodepsipeptide with potent antimethicillin-resistant Staphylococcus aureus (MRSA) activity and currently in phase I/II clinical trials. The WAP- 8294A2 biosynthetic genes had not been described previously. So far, the Gram-positive Streptomyces have been the primary source of anti-infectives. Lysobacter are Gram-negative soil/water bacteria that are genetically amendable and have not been well exploited. The WAP-8294A2 synthetase represents one of the largest NRPS complexes, consisting of 45 functional domains. The identification of these genes sets the foundation for the study of the WAP-8294A2 biosynthetic mechanism and opens the door for producing new anti-MRSA antibiotics through biosynthetic engineering in this new source of Lysobacter
The Nearest Neutron Star Candidate in a Binary Revealed by Optical Time-domain Surveys
Recent studies have revealed the global deposition on Earth of radioactive
elements (e.g., Fe) resulting from the metal-enriched ejecta of nearby
(within pc) supernova explosions. The majority of neutron stars in
our Solar neighborhood remain to be discovered. Here we report the discovery of
the nearest ( pc) neutron star candidate in the single-lined
spectroscopic binary LAMOST J235456.76+335625.7 (hereafter J2354). Utilizing
the multi-epoch spectra and high-cadence periodic light curves, we measure the
mass of the visible star () and determine
the mass function of the invisible object ,
i.e., the mass of the unseen compact object is $M_{\rm inv} \geq 1.26 \pm 0.03\
M_{\odot}0.12.4<10^{30}\ {\rm erg\ s^{-1}}1.4<6.8\times 10^{23}\ {\rm erg\ s^{-1}}$). Hence, the
neutron star candidate in J2354 can only be discovered via our time-resolved
observations. The alternative scenario involving a nearby supramassive cold
white dwarf cannot be fully excluded. Our discovery demonstrates a promising
way to unveil the missing population of backyard inactive neutron stars or
supramassive cold white dwarfs in binaries by exploring the optical time
domain, thereby facilitating understanding of the supernovae explosion and
metal-enrichment history in our Solar neighborhood.Comment: 35 pages, 8 figures, to be submitte
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