168 research outputs found
Hepatitis C Virus Evasion from RIG-I-Dependent Hepatic Innate Immunity
Exposure to hepatitis C virus (HCV) usually results in persistent infection that often develops into chronic liver disease. Interferon-alpha (IFN) treatment comprises the foundation of current approved therapy for chronic HCV infection but is limited in overall efficacy. IFN is a major effector of innate antiviral immunity and is naturally produced in response to viral infection when viral pathogen-associated molecular patterns (PAMPs) are recognized as nonself and are bound by cellular pathogen recognition receptors (PRRs), including Toll-like receptors (TLRs) and the RIG-I-like receptors (RLRs). Within hepatocytes, RIG-I is a major PRR of HCV infection wherein PAMP interactions serve to trigger intracellular signaling cascades in the infected hepatocyte to drive IFN production and the expression of interferon-stimulated genes (ISGs). ISGs function to limit virus replication, modulate the immune system, and to suppress virus spread. However, studies of HCV-host interactions have revealed several mechanisms of innate immune regulation and evasion that feature virus control of PRR signaling and regulation of hepatic innate immune programs that may provide a molecular basis for viral persistence
Density-invariant Features for Distant Point Cloud Registration
Registration of distant outdoor LiDAR point clouds is crucial to extending
the 3D vision of collaborative autonomous vehicles, and yet is challenging due
to small overlapping area and a huge disparity between observed point
densities. In this paper, we propose Group-wise Contrastive Learning (GCL)
scheme to extract density-invariant geometric features to register distant
outdoor LiDAR point clouds. We mark through theoretical analysis and
experiments that, contrastive positives should be independent and identically
distributed (i.i.d.), in order to train densityinvariant feature extractors. We
propose upon the conclusion a simple yet effective training scheme to force the
feature of multiple point clouds in the same spatial location (referred to as
positive groups) to be similar, which naturally avoids the sampling bias
introduced by a pair of point clouds to conform with the i.i.d. principle. The
resulting fully-convolutional feature extractor is more powerful and
density-invariant than state-of-the-art methods, improving the registration
recall of distant scenarios on KITTI and nuScenes benchmarks by 40.9% and
26.9%, respectively. Code is available at https://github.com/liuQuan98/GCL.Comment: In Proceedings of the IEEE/CVF International Conference on Computer
Vision (ICCV), 202
Graph Neural Network for Predicting the Effective Properties of Polycrystalline Materials: A Comprehensive Analysis
We develop a polycrystal graph neural network (PGNN) model for predicting the
effective properties of polycrystalline materials, using the Li7La3Zr2O12
ceramic as an example. A large-scale dataset with >5000 different
three-dimensional polycrystalline microstructures of finite-width grain
boundary is generated by Voronoi tessellation and processing of the electron
backscatter diffraction images. The effective ion conductivities and elastic
stiffness coefficients of these microstructures are calculated by
high-throughput physics-based simulations. The optimized PGNN model achieves a
low error of <1.4% in predicting all three diagonal components of the effective
Li-ion conductivity matrix, outperforming a linear regression model and two
baseline convolutional neural network models. Sequential forward selection
method is used to quantify the relative importance of selecting individual
grain (boundary) features to improving the property prediction accuracy,
through which both the critical and unwanted node (edge) feature can be
determined. The extrapolation performance of the trained PGNN model is also
investigated. The transfer learning performance is evaluated by using the PGNN
model pretrained for predicting conductivities to predict the elastic
properties of the same set of microstructures.Comment: 23 pages, 6 figures; added testing results on a new dataset and
sequential feature selectio
MoGDE: Boosting Mobile Monocular 3D Object Detection with Ground Depth Estimation
Monocular 3D object detection (Mono3D) in mobile settings (e.g., on a
vehicle, a drone, or a robot) is an important yet challenging task. Due to the
near-far disparity phenomenon of monocular vision and the ever-changing camera
pose, it is hard to acquire high detection accuracy, especially for far
objects. Inspired by the insight that the depth of an object can be well
determined according to the depth of the ground where it stands, in this paper,
we propose a novel Mono3D framework, called MoGDE, which constantly estimates
the corresponding ground depth of an image and then utilizes the estimated
ground depth information to guide Mono3D. To this end, we utilize a pose
detection network to estimate the pose of the camera and then construct a
feature map portraying pixel-level ground depth according to the 3D-to-2D
perspective geometry. Moreover, to improve Mono3D with the estimated ground
depth, we design an RGB-D feature fusion network based on the transformer
structure, where the long-range self-attention mechanism is utilized to
effectively identify ground-contacting points and pin the corresponding ground
depth to the image feature map. We conduct extensive experiments on the
real-world KITTI dataset. The results demonstrate that MoGDE can effectively
improve the Mono3D accuracy and robustness for both near and far objects. MoGDE
yields the best performance compared with the state-of-the-art methods by a
large margin and is ranked number one on the KITTI 3D benchmark.Comment: 36th Conference on Neural Information Processing Systems (NeurIPS),
2022. arXiv admin note: text overlap with arXiv:2303.1301
A Survey on Federated Unlearning: Challenges, Methods, and Future Directions
In recent years, the notion of ``the right to be forgotten" (RTBF) has
evolved into a fundamental element of data privacy regulations, affording
individuals the ability to request the removal of their personal data from
digital records. Consequently, given the extensive adoption of data-intensive
machine learning (ML) algorithms and increasing concerns for personal data
privacy protection, the concept of machine unlearning (MU) has gained
considerable attention. MU empowers an ML model to selectively eliminate
sensitive or personally identifiable information it acquired during the
training process. Evolving from the foundational principles of MU, federated
unlearning (FU) has emerged to confront the challenge of data erasure within
the domain of federated learning (FL) settings. This empowers the FL model to
unlearn an FL client or identifiable information pertaining to the client while
preserving the integrity of the decentralized learning process. Nevertheless,
unlike traditional MU, the distinctive attributes of federated learning
introduce specific challenges for FU techniques. These challenges lead to the
need for tailored design when designing FU algorithms. Therefore, this
comprehensive survey delves into the techniques, methodologies, and recent
advancements in federated unlearning. It provides an overview of fundamental
concepts and principles, evaluates existing federated unlearning algorithms,
reviews optimizations tailored to federated learning, engages in discussions
regarding practical applications, along with an assessment of their
limitations, and outlines promising directions for future research
DFlow: Efficient Dataflow-based Invocation Workflow Execution for Function-as-a-Service
The Serverless Computing is becoming increasingly popular due to its ease of
use and fine-grained billing. These features make it appealing for stateful
application or serverless workflow. However, current serverless workflow
systems utilize a controlflow-based invocation pattern to invoke functions. In
this execution pattern, the function invocation depends on the state of the
function. A function can only begin executing once all its precursor functions
have completed. As a result, this pattern may potentially lead to longer
end-to-end execution time. We design and implement the DFlow, a novel
dataflow-based serverless workflow system that achieves high performance for
serverless workflow. DFlow introduces a distributed scheduler (DScheduler) by
using the dataflow-based invocation pattern to invoke functions. In this
pattern, the function invocation depends on the data dependency between
functions. The function can start to execute even its precursor functions are
still running. DFlow further features a distributed store (DStore) that
utilizes effective fine-grained optimization techniques to eliminate function
interaction, thereby enabling efficient data exchange. With the support of
DScheduler and DStore, DFlow can achieving an average improvement of 60% over
CFlow, 40% over FaaSFlow, 25% over FaasFlowRedis, and 40% over KNIX on 99%-ile
latency respectively. Further, it can improve network bandwidth utilization by
2x-4x over CFlow and 1.5x-3x over FaaSFlow, FaaSFlowRedis and KNIX,
respectively. DFlow effectively reduces the cold startup latency, achieving an
average improvement of 5.6x over CFlow and 1.1x over FaaSFlowComment: 22 pages, 13 figure
Joint Optimization of Lifetime and Transport Delay under Reliability Constraint Wireless Sensor Networks
This paper first presents an analysis strategy to meet requirements of a sensing application through trade-offs between the energy consumption (lifetime) and source-to-sink transport delay under reliability constraint wireless sensor networks. A novel data gathering protocol named Broadcasting Combined with Multi-NACK/ACK (BCMN/A) protocol is proposed based on the analysis strategy. The BCMN/A protocol achieves energy and delay efficiency during the data gathering process both in intra-cluster and inter-cluster. In intra-cluster, after each round of TDMA collection, a cluster head broadcasts NACK to indicate nodes which fail to send data in order to prevent nodes that successfully send data from retransmission. The energy for data gathering in intra-cluster is conserved and transport delay is decreased with multi-NACK mechanism. Meanwhile in inter-clusters, multi-ACK is returned whenever a sensor node sends any data packet. Although the number of ACKs to be sent is increased, the number of data packets to be retransmitted is significantly decreased so that consequently it reduces the node energy consumption. The BCMN/A protocol is evaluated by theoretical analysis as well as extensive simulations and these results demonstrate that our proposed protocol jointly optimizes the network lifetime and transport delay under network reliability constraint
The Molecular Basis of Viral Inhibition of IRF- and STAT-Dependent Immune Responses
The antiviral innate immunity is the first line of host defense against virus infections. In mammalian cells, viral infections initiate the expression of interferons (IFNs) in the host that in turn activate an antiviral defense program to restrict viral replications by induction of IFN stimulated genes (ISGs), which are largely regulated by the IFN-regulatory factor (IRF) family and signal transducer and activator of transcription (STAT) family transcription factors. The mechanisms of action of IRFs and STATs involve several post-translational modifications, complex formation, and nuclear translocation of these transcription factors. However, many viruses, including human immunodeficiency virus (HIV), Zika virus (ZIKV), and herpes simplex virus (HSV), have evolved strategies to evade host defense, including alteration in IRF and STAT post-translational modifications, disturbing the formation and nuclear translocation of the transcription complexes as well as proteolysis/degradation of IRFs and STATs. In this review, we discuss and summarize the molecular mechanisms by which how viral components may target IRFs and STATs to antagonize the establishment of antiviral host defense. The underlying host-viral interactions determine the outcome of viral infection. Gaining mechanistic insight into these processes will be crucial in understanding how viral replication can be more effectively controlled and in developing approaches to improve virus infection outcomes
Toll-like receptor 4 mediates synergism between alcohol and HCV in hepatic oncogenesis involving stem cell marker Nanog
Alcohol synergistically enhances the progression of liver disease and the risk for liver cancer caused by hepatitis C virus (HCV). However, the molecular mechanism of this synergy remains unclear. Here, we provide the first evidence that Toll-like receptor 4 (TLR4) is induced by hepatocyte-specific transgenic (Tg) expression of the HCV nonstructural protein NS5A, and this induction mediates synergistic liver damage and tumor formation by alcohol-induced endotoxemia. We also identify Nanog, the stem/progenitor cell marker, as a novel downstream gene up-regulated by TLR4 activation and the presence of CD133/Nanog-positive cells in liver tumors of alcohol-fed NS5A Tg mice. Transplantation of p53-deficient hepatic progenitor cells transduced with TLR4 results in liver tumor development in mice following repetitive LPS injection, but concomitant transduction of Nanog short-hairpin RNA abrogates this outcome. Taken together, our study demonstrates a TLR4-dependent mechanism of synergistic liver disease by HCV and alcohol and an obligatory role for Nanog, a TLR4 downstream gene, in HCV-induced liver oncogenesis enhanced by alcohol
- …