78 research outputs found

    Optimizing Image Compression via Joint Learning with Denoising

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    High levels of noise usually exist in today's captured images due to the relatively small sensors equipped in the smartphone cameras, where the noise brings extra challenges to lossy image compression algorithms. Without the capacity to tell the difference between image details and noise, general image compression methods allocate additional bits to explicitly store the undesired image noise during compression and restore the unpleasant noisy image during decompression. Based on the observations, we optimize the image compression algorithm to be noise-aware as joint denoising and compression to resolve the bits misallocation problem. The key is to transform the original noisy images to noise-free bits by eliminating the undesired noise during compression, where the bits are later decompressed as clean images. Specifically, we propose a novel two-branch, weight-sharing architecture with plug-in feature denoisers to allow a simple and effective realization of the goal with little computational cost. Experimental results show that our method gains a significant improvement over the existing baseline methods on both the synthetic and real-world datasets. Our source code is available at https://github.com/felixcheng97/DenoiseCompression.Comment: Accepted to ECCV 202

    DYNAFED: Tackling Client Data Heterogeneity with Global Dynamics

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    The Federated Learning (FL) paradigm is known to face challenges under heterogeneous client data. Local training on non-iid distributed data results in deflected local optimum, which causes the client models drift further away from each other and degrades the aggregated global model's performance. A natural solution is to gather all client data onto the server, such that the server has a global view of the entire data distribution. Unfortunately, this reduces to regular training, which compromises clients' privacy and conflicts with the purpose of FL. In this paper, we put forth an idea to collect and leverage global knowledge on the server without hindering data privacy. We unearth such knowledge from the dynamics of the global model's trajectory. Specifically, we first reserve a short trajectory of global model snapshots on the server. Then, we synthesize a small pseudo dataset such that the model trained on it mimics the dynamics of the reserved global model trajectory. Afterward, the synthesized data is used to help aggregate the deflected clients into the global model. We name our method Dynafed, which enjoys the following advantages: 1) we do not rely on any external on-server dataset, which requires no additional cost for data collection; 2) the pseudo data can be synthesized in early communication rounds, which enables Dynafed to take effect early for boosting the convergence and stabilizing training; 3) the pseudo data only needs to be synthesized once and can be directly utilized on the server to help aggregation in subsequent rounds. Experiments across extensive benchmarks are conducted to showcase the effectiveness of Dynafed. We also provide insights and understanding of the underlying mechanism of our method

    Security enhanced sentence similarity computing model based on convolutional neural network

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    Deep learning model shows great advantages in various fields. However, researchers pay attention to how to improve the accuracy of the model, while ignoring the security considerations. The problem of controlling the judgment result of deep learning model by attack examples and then affecting the system decision-making is gradually exposed. In order to improve the security of sentence similarity analysis model, we propose a convolution neural network model based on attention mechanism. First of all, the mutual information between sentences is correlated by attention weighting. Then, it is input into improved convolutional neural network. In addition, we add attack examples to the input, which is generated by the firefly algorithm. In the attack example, we replace the words in the sentence to some extent, which results in the adversarial data with great semantic change but slight sentence structure change. To a certain extent, the addition of attack example increases the ability of model to identify adversarial data and improves the robustness of the model. Experimental results show that the accuracy, recall rate and F1 value of the model are due to other baseline models.This work was supported in part by the Major Scientific and Technological Projects of China National Petroleum Corporation (CNPC) under Grant ZD2019-183-006, in part by the Shandong Provincial Natural Science Foundation, China, under Grant ZR2020MF006, in part by the Fundamental Research Funds for the Central Universities of China University of Petroleum (East China) under Grant 20CX05017A, and in part by the Open Foundation of State Key Laboratory of Networking and Switching Technology (Beijing University of Posts and Telecommunications) under Grant SKLNST-2021-1-17.Postprint (author's final draft

    Observing the air-sea turbulent heat flux on the trajectory of tropical storm Danas

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    Tropical cyclones constitute a major risk for coastal communities. To assess their damage potential, accurate predictions of their intensification are needed, which requires a detailed understanding of the evolution of turbulent heat flux (THF). By combining multiple buoy observations along the south-north storm track, we investigated the THF anomalies associated with tropical storm Danas (2019) in the East China Sea (ECS) during its complete life cycle from the intensification stage to the mature stage and finally to its dissipation on land. The storm passage is characterized by strong winds of 10–20 m/s and a sea level pressure below 1 000 hPa, resulting in a substantial enhancement of THF. Latent heat (LH) fluxes are most strongly affected by wind speed, with a gradually increasing contribution of humidity along the trajectory. The relative contributions of wind speed and temperature anomalies to sensible heat (SH) depend on the stability of the boundary layer. Under stable conditions, SH variations are driven by wind speed, while under near-neutral conditions, SH variations are driven by temperature. A comparison of the observed THF and associated variables with outputs from the ERA5 and MERRA2 reanalysis products reveals that the reanalysis products can reproduce the basic evolution and composition of the observed THF. However, under extreme weather conditions, temperature and humidity variations are poorly captured by ERA5 and MERRA2, leading to large LH and SH errors. The differences in the observed and reproduced LH and SH during the passage of Danas amount to 26.1 and 6.6 W/m2 for ERA5, respectively, and to 39.4 and 12.5 W/m2 for MERRA2, respectively. These results demonstrate the need to improve the representation of tropical cyclones in reanalysis products to better predict their intensification process and reduce their damage

    Coagulation factor IX gene transfer to non-human primates using engineered AAV3 capsid and hepatic optimized expression cassette

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    Hepatic gene transfer with adeno-associated viral (AAV) vectors shows much promise for the treatment of the X-linked bleeding disorder hemophilia B in multiple clinical trials. In an effort to further innovate this approach and to introduce alternative vector designs with potentially superior features into clinical development, we recently built a vector platform based on AAV serotype 3 because of its superior tropism for human hepatocytes. A vector genome with serotype-matched inverted terminal repeats expressing hyperactive human coagulation factor IX (FIX)-Padua was designed for clinical use that is optimized for translation using hepatocyte-specific codon-usage bias and is depleted of immune stimulatory CpG motifs. Here, this vector genome was packaged into AAV3 (T492V + S663V) capsid for hepatic gene transfer in non-human primates. FIX activity within or near the normal range was obtained at a low vector dose of 5 x 10(11) vector genomes/kg. Pre-existing neutralizing antibodies, however, completely or partially blocked hepatic gene transfer at that dose. No CD8(+) T cell response against capsid was observed. Antibodies against the human FIX transgene product formed at a 10-fold higher vector dose, albeit hepatic gene transfer was remarkably consistent, and sustained FIX activity in the normal range was nonetheless achieved in two of three animals for the 3-month duration of the study. These results support the use of this vector at low vector doses for gene therapy of hemophilia B in humans

    Municipal solid waste management under Covid-19: Challenges and recommendations

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    Covid-19 is proving to be an unprecedented disaster for human health, social contacts and the economy worldwide. It is evident that SARS-CoV-2 may spread through municipal solid waste (MSW), if collected, bagged, handled, transported or disposed of inappropriately. Under the stress placed by the current pandemic on the sanitary performance across all MSW management (MSWM) chains, this industry needs to re-examine its infrastructure resilience with respect to all processes, from waste identification, classification, collection, separation, storage, transportation, recycling, treatment and disposal. The current paper provides an overview of the severe challenges placed by Covid-19 onto MSW systems, highlighting the essential role of waste management in public health protection during the ongoing pandemic. It also discusses the measures issued by various international organisations and countries for the protection of MSWM employees (MSWEs), identifying gaps, especially for developing countries, where personal protection equipment and clear guidelines to MSWEs may not have been provided, and the general public may not be well informed. In countries with high recycling rates of MSW, the need to protect MSWEs' health has affected the supply stream of the recycling industry. The article concludes with recommendations for the MSW industry operating under public health crisis conditions

    Significant decrease of maternal mitochondria carryover using optimized spindle-chromosomal complex transfer.

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    Mutations in mitochondrial DNA (mtDNA) contribute to a variety of serious multi-organ human diseases, which are strictly inherited from the maternal germline. However, there is currently no curative treatment. Attention has been focused on preventing the transmission of mitochondrial diseases through mitochondrial replacement (MR) therapy, but levels of mutant mtDNA can often unexpectedly undergo significant changes known as mitochondrial genetic drift. Here, we proposed a novel strategy to perform spindle-chromosomal complex transfer (SCCT) with maximal residue removal (MRR) in metaphase II (MII) oocytes, thus hopefully eliminated the transmission of mtDNA diseases. With the MRR procedure, we initially investigated the proportions of mtDNA copy numbers in isolated karyoplasts to those of individual oocytes. Spindle-chromosomal morphology and copy number variation (CNV) analysis also confirmed the safety of this method. Then, we reconstructed oocytes by MRR-SCCT, which well developed to blastocysts with minimal mtDNA residue and normal chromosomal copy numbers. Meanwhile, we optimized the manipulation order between intracytoplasmic sperm injection (ICSI) and SCC transfer and concluded that ICSI-then-transfer was conducive to avoid premature activation of reconstructed oocytes in favor of normal fertilization. Offspring of mice generated by embryos transplantation in vivo and embryonic stem cells derivation further presented evidences for competitive development competence and stable mtDNA carryover without genetic drift. Importantly, we also successfully accomplished SCCT in human MII oocytes resulting in tiny mtDNA residue and excellent embryo development through MRR manipulation. Taken together, our preclinical mouse and human models of the MRR-SCCT strategy not only demonstrated efficient residue removal but also high compatibility with normal embryo development, thus could potentially be served as a feasible clinical treatment to prevent the transmission of inherited mtDNA diseases
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