胎儿肺扩散加权MRI(DWI)数据的定量分析显示,提供了提供的定量成像生物标志物,这些生物标志物间接反映了胎儿肺的成熟。但是,采集期间的胎儿运动阻碍了对获得的DWI数据的定量分析,因此妨碍了可靠的临床利用。我们介绍了QDWI-Morph,这是一种无监督的深神经网络结构,用于运动补偿定量DWI(QDWI)分析。我们的方法将注册子网络与定量DWI模型拟合子网络融合。我们同时估计QDWI参数和运动模型,通过最大程度地降低整合注册损失和模型拟合质量损失的生物形态信息损失函数。我们证明了QDWI-MORPH的附加值:1)基线QDWI分析没有运动补偿和2)仅包含注册损失的基线深学习模型。 QDWI-morph通过对胎儿肺DWI数据的体内QDWI分析(r-squared = 0.32 vs. 0.13,0.28)实现了与胎龄的相关性。我们的QDWI-MORPH有可能对DWI数据进行运动补偿的定量分析,并为非侵入性胎儿肺成熟度评估提供临床上可行的生物标志物。我们的代码可在以下网址获得:https://github.com/technioncomputationalmrilab/qdwi-morph。
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对胎儿肺扩散加权MRI(DWI)的数据分析(IVIM)分析显示了提供定量成像的生物标志物的潜力,这些标志物是间接地反映出非侵入性胎儿肺肺部成熟评估的扩散和伪扩散的。然而,由于IVIM分析所需的大量不同的“ B值”图像,较长的获取时间,排除了临床可行性。我们介绍了Super-IVIM-DC一种深神经网络(DNN)方法,该方法将监督损失与数据矛盾项相结合,以实现IVIM分析以有限数量的B值获得的DWI数据。我们通过数值模拟,健康的志愿者研究和IVIM分析了胎儿DWI数据的胎儿肺成熟,从而证明了超级IVIM-DC在经典和最近的DNN方法中的附加价值。 %添加结果我们的数值模拟和健康的志愿者研究表明,与以前的基于DNN的方法相比,来自有限DWI数据的IVIM模型参数的超级IVIM-DC估计值较低。此外,与经典和基于DNN的方法相比,胎儿肺有限的DWI数据的伪扩散分数参数的超级IVIM-DC估计与胎龄相关(0.242 vs. -0.079和0.239)。 Super-IVIM-DC有可能减少与IVIM数据分析DWI数据相关的长期获取时间,并为非侵入性胎儿肺成熟度评估提供临床上可行的生物标志物。
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肾脏DCE-MRI旨在通过估计示踪动力学(TK)模型参数来定义评估肾脏解剖学和对肾功能的定量评估。 TK模型参数的准确估计需要具有高时间分辨率的动脉输入功能(AIF)的精确测量。加速成像用于实现高时间分辨率,其在重建图像中产生欠采样伪像。压缩传感(CS)方法提供各种重建选项。最常见的是,鼓励正规化的时间差异的稀疏性以减少伪影。在CS方法中越来越多的正则化除去环境伪像,但也会过度平滑时间,这减少了参数估计精度。在这项工作中,我们提出了一种训练有素的深神经网络,以减少MRI欠采样伪像而不降低功能成像标记的准确性。通过从较低的维度表示,我们通过从较低维度表示来促进正常化而不是在惩罚术语中进行规范化。在此手稿中,我们激励并解释了较低的维度输入设计。我们将我们的方法与多个正则化权重进行CS重建的方法。所提出的方法导致肾生物标志物与使用CS重建估计的地面真理标记高度相关,这是针对功能分析进行了优化的。同时,所提出的方法减少了重建图像中的伪像。
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Continuous long-term monitoring of motor health is crucial for the early detection of abnormalities such as bearing faults (up to 51% of motor failures are attributed to bearing faults). Despite numerous methodologies proposed for bearing fault detection, most of them require normal (healthy) and abnormal (faulty) data for training. Even with the recent deep learning (DL) methodologies trained on the labeled data from the same machine, the classification accuracy significantly deteriorates when one or few conditions are altered. Furthermore, their performance suffers significantly or may entirely fail when they are tested on another machine with entirely different healthy and faulty signal patterns. To address this need, in this pilot study, we propose a zero-shot bearing fault detection method that can detect any fault on a new (target) machine regardless of the working conditions, sensor parameters, or fault characteristics. To accomplish this objective, a 1D Operational Generative Adversarial Network (Op-GAN) first characterizes the transition between normal and fault vibration signals of (a) source machine(s) under various conditions, sensor parameters, and fault types. Then for a target machine, the potential faulty signals can be generated, and over its actual healthy and synthesized faulty signals, a compact, and lightweight 1D Self-ONN fault detector can then be trained to detect the real faulty condition in real time whenever it occurs. To validate the proposed approach, a new benchmark dataset is created using two different motors working under different conditions and sensor locations. Experimental results demonstrate that this novel approach can accurately detect any bearing fault achieving an average recall rate of around 89% and 95% on two target machines regardless of its type, severity, and location.
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Basecalling is an essential step in nanopore sequencing analysis where the raw signals of nanopore sequencers are converted into nucleotide sequences, i.e., reads. State-of-the-art basecallers employ complex deep learning models to achieve high basecalling accuracy. This makes basecalling computationally-inefficient and memory-hungry; bottlenecking the entire genome analysis pipeline. However, for many applications, the majority of reads do no match the reference genome of interest (i.e., target reference) and thus are discarded in later steps in the genomics pipeline, wasting the basecalling computation. To overcome this issue, we propose TargetCall, the first fast and widely-applicable pre-basecalling filter to eliminate the wasted computation in basecalling. TargetCall's key idea is to discard reads that will not match the target reference (i.e., off-target reads) prior to basecalling. TargetCall consists of two main components: (1) LightCall, a lightweight neural network basecaller that produces noisy reads; and (2) Similarity Check, which labels each of these noisy reads as on-target or off-target by matching them to the target reference. TargetCall filters out all off-target reads before basecalling; and the highly-accurate but slow basecalling is performed only on the raw signals whose noisy reads are labeled as on-target. Our thorough experimental evaluations using both real and simulated data show that TargetCall 1) improves the end-to-end basecalling performance of the state-of-the-art basecaller by 3.31x while maintaining high (98.88%) sensitivity in keeping on-target reads, 2) maintains high accuracy in downstream analysis, 3) precisely filters out up to 94.71% of off-target reads, and 4) achieves better performance, sensitivity, and generality compared to prior works. We freely open-source TargetCall at https://github.com/CMU-SAFARI/TargetCall.
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To achieve autonomy in a priori unknown real-world scenarios, agents should be able to: i) act from high-dimensional sensory observations (e.g., images), ii) learn from past experience to adapt and improve, and iii) be capable of long horizon planning. Classical planning algorithms (e.g. PRM, RRT) are proficient at handling long-horizon planning. Deep learning based methods in turn can provide the necessary representations to address the others, by modeling statistical contingencies between observations. In this direction, we introduce a general-purpose planning algorithm called PALMER that combines classical sampling-based planning algorithms with learning-based perceptual representations. For training these perceptual representations, we combine Q-learning with contrastive representation learning to create a latent space where the distance between the embeddings of two states captures how easily an optimal policy can traverse between them. For planning with these perceptual representations, we re-purpose classical sampling-based planning algorithms to retrieve previously observed trajectory segments from a replay buffer and restitch them into approximately optimal paths that connect any given pair of start and goal states. This creates a tight feedback loop between representation learning, memory, reinforcement learning, and sampling-based planning. The end result is an experiential framework for long-horizon planning that is significantly more robust and sample efficient compared to existing methods.
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Gathering properly labelled, adequately rich, and case-specific data for successfully training a data-driven or hybrid model for structural health monitoring (SHM) applications is a challenging task. We posit that a Transfer Learning (TL) method that utilizes available data in any relevant source domain and directly applies to the target domain through domain adaptation can provide substantial remedies to address this issue. Accordingly, we present a novel TL method that differentiates between the source's no-damage and damage cases and utilizes a domain adaptation (DA) technique. The DA module transfers the accumulated knowledge in contrasting no-damage and damage cases in the source domain to the target domain, given only the target's no-damage case. High-dimensional features allow employing signal processing domain knowledge to devise a generalizable DA approach. The Generative Adversarial Network (GAN) architecture is adopted for learning since its optimization process accommodates high-dimensional inputs in a zero-shot setting. At the same time, its training objective conforms seamlessly with the case of no-damage and damage data in SHM since its discriminator network differentiates between real (no damage) and fake (possibly unseen damage) data. An extensive set of experimental results demonstrates the method's success in transferring knowledge on differences between no-damage and damage cases across three strongly heterogeneous independent target structures. The area under the Receiver Operating Characteristics curves (Area Under the Curve - AUC) is used to evaluate the differentiation between no-damage and damage cases in the target domain, reaching values as high as 0.95. With no-damage and damage cases discerned from each other, zero-shot structural damage detection is carried out. The mean F1 scores for all damages in the three independent datasets are 0.978, 0.992, and 0.975.
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Resistive Random-Access Memory (RRAM) is well-suited to accelerate neural network (NN) workloads as RRAM-based Processing-in-Memory (PIM) architectures natively support highly-parallel multiply-accumulate (MAC) operations that form the backbone of most NN workloads. Unfortunately, NN workloads such as transformers require support for non-MAC operations (e.g., softmax) that RRAM cannot provide natively. Consequently, state-of-the-art works either integrate additional digital logic circuits to support the non-MAC operations or offload the non-MAC operations to CPU/GPU, resulting in significant performance and energy efficiency overheads due to data movement. In this work, we propose NEON, a novel compiler optimization to enable the end-to-end execution of the NN workload in RRAM. The key idea of NEON is to transform each non-MAC operation into a lightweight yet highly-accurate neural network. Utilizing neural networks to approximate the non-MAC operations provides two advantages: 1) We can exploit the key strength of RRAM, i.e., highly-parallel MAC operation, to flexibly and efficiently execute non-MAC operations in memory. 2) We can simplify RRAM's microarchitecture by eliminating the additional digital logic circuits while reducing the data movement overheads. Acceleration of the non-MAC operations in memory enables NEON to achieve a 2.28x speedup compared to an idealized digital logic-based RRAM. We analyze the trade-offs associated with the transformation and demonstrate feasible use cases for NEON across different substrates.
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A new development in NLP is the construction of hyperbolic word embeddings. As opposed to their Euclidean counterparts, hyperbolic embeddings are represented not by vectors, but by points in hyperbolic space. This makes the most common basic scheme for constructing document representations, namely the averaging of word vectors, meaningless in the hyperbolic setting. We reinterpret the vector mean as the centroid of the points represented by the vectors, and investigate various hyperbolic centroid schemes and their effectiveness at text classification.
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Facial recognition is fundamental for a wide variety of security systems operating in real-time applications. In video surveillance based face recognition, face images are typically captured over multiple frames in uncontrolled conditions; where head pose, illumination, shadowing, motion blur and focus change over the sequence. We can generalize that the three fundamental operations involved in the facial recognition tasks: face detection, face alignment and face recognition. This study presents comparative benchmark tables for the state-of-art face recognition methods by testing them with same backbone architecture in order to focus only on the face recognition solution instead of network architecture. For this purpose, we constructed a video surveillance dataset of face IDs that has high age variance, intra-class variance (face make-up, beard, etc.) with native surveillance facial imagery data for evaluation. On the other hand, this work discovers the best recognition methods for different conditions like non-masked faces, masked faces, and faces with glasses.
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