In the brain, information is encoded, transmitted and used to inform behaviour at the level of timing of action potentials distributed over population of neurons. To implement neural-like systems in silico, to emulate neural function, and to interface successfully with the brain, neuromorphic circuits need to encode information in a way compatible to that used by populations of neuron in the brain. To facilitate the cross-talk between neuromorphic engineering and neuroscience, in this Review we first critically examine and summarize emerging recent findings about how population of neurons encode and transmit information. We examine the effects on encoding and readout of information for different features of neural population activity, namely the sparseness of neural representations, the heterogeneity of neural properties, the correlations among neurons, and the time scales (from short to long) at which neurons encode information and maintain it consistently over time. Finally, we critically elaborate on how these facts constrain the design of information coding in neuromorphic circuits. We focus primarily on the implications for designing neuromorphic circuits that communicate with the brain, as in this case it is essential that artificial and biological neurons use compatible neural codes. However, we also discuss implications for the design of neuromorphic systems for implementation or emulation of neural computation.

We study the multiclass classification problem where the features come from the mixture of time-homogeneous diffusions. Specifically, the classes are discriminated by their drift functions while the diffusion coefficient is common to all classes and unknown. In this framework, we build a plug-in classifier which relies on nonparametric estimators of the drift and diffusion functions. We first establish the consistency of our classification procedure under mild assumptions and then provide rates of cnvergence under different set of assumptions. Finally, a numerical study supports our theoretical findings.

The post-training quantization (PTQ) challenge of bringing quantized neural net accuracy close to original has drawn much attention driven by industry demand. Many of the methods emphasize optimization of a specific degree-of-freedom (DoF), such as quantization step size, preconditioning factors, bias fixing, often chained to others in multi-step solutions. Here we rethink quantized network parameterization in HW-aware fashion, towards a unified analysis of all quantization DoF, permitting for the first time their joint end-to-end finetuning. Our single-step simple and extendable method, dubbed quantization-aware finetuning (QFT), achieves 4-bit weight quantization results on-par with SoTA within PTQ constraints of speed and resource.

Question answering models commonly have access to two sources of "knowledge" during inference time: (1) parametric knowledge - the factual knowledge encoded in the model weights, and (2) contextual knowledge - external knowledge (e.g., a Wikipedia passage) given to the model to generate a grounded answer. Having these two sources of knowledge entangled together is a core issue for generative QA models as it is unclear whether the answer stems from the given non-parametric knowledge or not. This unclarity has implications on issues of trust, interpretability and factuality. In this work, we propose a new paradigm in which QA models are trained to disentangle the two sources of knowledge. Using counterfactual data augmentation, we introduce a model that predicts two answers for a given question: one based on given contextual knowledge and one based on parametric knowledge. Our experiments on the Natural Questions dataset show that this approach improves the performance of QA models by making them more robust to knowledge conflicts between the two knowledge sources, while generating useful disentangled answers.

Electrocardiography (ECG), an electrical measurement which captures cardiac activities, is the gold standard for diagnosing cardiovascular disease (CVD). However, ECG is infeasible for continuous cardiac monitoring due to its requirement for user participation. By contrast, photoplethysmography (PPG) provides easy-to-collect data, but its limited accuracy constrains its clinical usage. To combine the advantages of both signals, recent studies incorporate various deep learning techniques for the reconstruction of PPG signals to ECG; however, the lack of contextual information as well as the limited abilities to denoise biomedical signals ultimately constrain model performance. In this research, we propose Performer, a novel Transformer-based architecture that reconstructs ECG from PPG and combines the PPG and reconstructed ECG as multiple modalities for CVD detection. This method is the first time that Transformer sequence-to-sequence translation has been performed on biomedical waveform reconstruction, combining the advantages of both PPG and ECG. We also create Shifted Patch-based Attention (SPA), an effective method to encode/decode the biomedical waveforms. Through fetching the various sequence lengths and capturing cross-patch connections, SPA maximizes the signal processing for both local features and global contextual representations. The proposed architecture generates a state-of-the-art performance of 0.29 RMSE for the reconstruction of PPG to ECG on the BIDMC database, surpassing prior studies. We also evaluated this model on the MIMIC-III dataset, achieving a 95.9% accuracy in CVD detection, and on the PPG-BP dataset, achieving 75.9% accuracy in related CVD diabetes detection, indicating its generalizability. As a proof of concept, an earring wearable named PEARL (prototype), was designed to scale up the point-of-care (POC) healthcare system.

在自主驾驶中，在使用深神经网络的爆炸中爆炸用于感知，预测和规划任务。由于自主车辆（AVS）更接近生产，多模态传感器输入和具有不同传感器平台的异构车队在该行业中变得越来越普遍。然而，神经网络架构通常是针对特定的传感器平台，并且对输入的变化并不稳健，使得缩放和模型部署的问题特别困难。此外，大多数玩家仍然将软件和硬件的问题视为完全独立的问题。我们提出了一个新的终端架构，广义传感器融合（GSF），其设计成使得传感器输入和目标任务都是模块化和可修改的。这使AV系统设计人员能够轻松地使用不同的传感器配置和方法进行实验，并使用在大型工程组织中共享的相同型号开辟了在异构船队上部署的能力。使用该系统，我们报告了实验结果，我们展示了昂贵的高密度（HD）激光雷达传感器的近似奇偶阶段，具有3D对象检测任务中的廉价低密度（LD）LIDAR加相机设置。这为行业铺平了道路，共同设计硬件和软件架构以及具有异质配置的大船队。

由于能够提高几个诊断任务的性能，深度神经网络越来越多地被用作医疗保健应用中的辅助工具。然而，由于基于深度学习系统的可靠性，概括性和可解释性的实际限制，这些方法在临床环境中不被广泛采用。因此，已经开发了方法，这在网络培训期间强加了额外的限制，以获得更多的控制，并改善探讨他们在医疗界的接受。在这项工作中，我们调查使用正交球（OS）约束对胸部X射线图像进行Covid-19案例的分类的益处。 OS约束可以写成一个简单的正交性术语，其与分类网络训练期间的标准交叉熵损耗结合使用。以前的研究表明，在对深度学习模型上对这种限制应用于应用这些限制方面表现出显着的益处。我们的研究结果证实了这些观察结果，表明正常性损失函数有效地通过Gradcam可视化，增强的分类性能和减少的模型校准误差产生了改进的语义本地化。我们的方法分别实现了两性和三类分类的准确性提高1.6％和4.8％;找到了应用数据增强的模型的类似结果。除了这些发现之外，我们的工作还提出了OS规范器在医疗保健中的新应用，提高了CoVID-19分类深度学习模型的后HOC可解释性和性能，以便于在临床环境中采用这些方法。我们还确定了我们将来可以探索进一步研究的战略的局限性。