3,193 research outputs found

    Flexible Yet Secure De-Duplication Service for Enterprise Data on Cloud Storage

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    The cloud storage services bring forth infinite storage capacity and flexible access capability to store and share large-scale content. The convenience brought forth has attracted both individual and enterprise users to outsource data service to a cloud provider. As the survey shows 56% of the usages of cloud storage applications are for data back up and up to 68% of data backup are user assets. Enterprise tenants would need to protect their data privacy before uploading them to the cloud and expect a reasonable performance while they try to reduce the operation cost in terms of cloud storage, capacity and I/Os matter as well as systems’ performance, bandwidth and data protection. Thus, enterprise tenants demand secure and economic data storage yet flexible access on their cloud data. In this paper, we propose a secure de-duplication solution for enterprise tenants to leverage the benefits of cloud storage while reducing operation cost and protecting privacy. First, the solution uses a proxy to do flexible group access control which supports secure de-duplication within a group; Second, the solution supports scalable clustering of proxies to support large-scale data access; Third, the solution can be integrated with cloud storage seamlessly. We implemented and tested our solution by integrating it with Dropbox. Secure de-duplication in a group is performed at low data transfer latency and small storage overhead as compared to de-duplication on plaintext

    A Cloud Authentication Protocol using One-Time Pad

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    There is a significant increase in the amount of data breaches in corporate servers in the cloud environments. This includes username and password compromise in the cloud and account hijacking, thus leading to severe vulnerabilities of the cloud service provisioning. Traditional authentication schemes rely on the users to use their credentials to gain access to cloud service. However once the credential is compromised, the attacker will gain access to the cloud service easily. This paper proposes a novel scheme that does not require the user to present his credentials, and yet is able to prove ownership of access to the cloud service using a variant of zero-knowledge proof. A challenge-response protocol is devised to authenticate the user, requiring the user to compute a one-time pad (OTP) to authenticate himself to the server without revealing password to the server. A prototype has been implemented to facilitate the authentication of the user when accessing Dropbox, and the experiment results showed that the overhead incurred is insignificant

    Effects of different concentrations of topotactic hydrogen impurities on the electronic structure of nickelate superconductors

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    Infinite-layer nickelate superconductors have recently been discovered to share both similarities and differences with cuprate superconductors. Notably, the incorporation of hydrogen (H) through topotactic reduction has been found to play a critical role in their electronic structure and, consequently, their superconductivity. In this study, we utilized a theoretical approach combining density-functional theory and impurity approximation to design three characteristic multi-orbital Hubbard models representing low, moderate, and high concentrations of topotactic-hydrogen. Consistent with experimental findings, our simulations revealed that both low and high concentrations of topotactic-hydrogen induce high-spin states (SS=1) that are composed by holes at dx2y2d_{x^2-y^2} and dz2d_{z^2} orbitals and consequently the emergent inter-site hopping between dz2d_{z^2} to dx2y2d_{x^2-y^2} is unfavorable for superconductivity. Conversely, an optimal concentration of 25\% H aligns with the single Ni-dx2y2d_{x^2-y^2} band picture of superconductivity in infinite-layer nickelates, demonstrating its beneficial effect on promoting superconducting behavior.Comment: 9 pages, 6 figure

    Flexible Yet Secure De-Duplication Service for Enterprise Data on Cloud Storage

    Get PDF
    The cloud storage services bring forth infinite storage capacity and flexible access capability to store and share large-scale content. The convenience brought forth has attracted both individual and enterprise users to outsource data service to a cloud provider. As the survey shows 56% of the usages of cloud storage applications are for data back up and up to 68% of data backup are user assets. Enterprise tenants would need to protect their data privacy before uploading them to the cloud and expect a reasonable performance while they try to reduce the operation cost in terms of cloud storage, capacity and I/Os matter as well as systems’ performance, bandwidth and data protection. Thus, enterprise tenants demand secure and economic data storage yet flexible access on their cloud data. In this paper, we propose a secure de-duplication solution for enterprise tenants to leverage the benefits of cloud storage while reducing operation cost and protecting privacy. First, the solution uses a proxy to do flexible group access control which supports secure de-duplication within a group; Second, the solution supports scalable clustering of proxies to support large-scale data access; Third, the solution can be integrated with cloud storage seamlessly. We implemented and tested our solution by integrating it with Dropbox. Secure de-duplication in a group is performed at low data transfer latency and small storage overhead as compared to de-duplication on plaintext

    Dysfunction of the Clinical Effect of Levonorgestrel Treatment of Dysfunctional Uterine Bleeding

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    Objective: Study clinical curative effect of levonorgestrel treatment on perimenopausal dysfunctional uterine bleeding. Method: Selected 126 outpatient of dysfunctional uterine bleeding which hospitalize from December 2010 to December 2012 at department of gynaecology to undergo levonorgestrel treatment on the 5‒7 days of menstruation. The endometrial thickness, hemoglobin, and the PBAC score of before and 3, 6, and 12 months after placement were observed and recorded. To observation the adverse reactions after levonorgestrel treatment. Results: After treatment, the thickness of the endometrium, the amount of menstruation and the hemoglobin concentration increased in 126 patients. During the treatment, 21 patients experienced mild dizziness and nausea, but did not affect the drug use and efficacy. Conclusion: Effects of levonorgestrel on intrauterine treatment of perimenopausal dysfunctional uterine bleeding can effectively reduce the amount of menstruation and increase hemoglobin levels. It is economic, simple, less adverse reaction, and widely entrenched in clinical practice

    Ultrasound cavitation induced nucleation in metal solidification: an analytical model and validation by real-time experiments

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    Microstructural refinement of metallic alloys via ultrasonic melt processing (USMP) is an environmentally friendly and promising method. However, so far there has been no report in open literature on how to predict the solidified microstructures and grain size based on the ultrasound processing parameters.In this paper, an analytical model is developed to calculate the cavitation enhanced undercooling and the USMP refined solidification microstructure and grain size for Al-Cu alloys. Ultrafast synchrotron X-ray imaging and tomography techniques were used to collect the real-time experimental data for validating the model and the calculated results. The comparison between modeling and experiments reveal that there exists an effective ultrasound input power intensity for maximizing the grain refinement effects for the Al-Cu alloys, which is in the range of 20-45 MW/m2. In addition, a monotonous increase in temperature during USMP has negative effect on producing new nuclei, deteriorating the benefit of microstructure refinement due to the application of ultrasound

    Position-Enhanced Visual Instruction Tuning for Multimodal Large Language Models

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    Recently, Multimodal Large Language Models (MLLMs) that enable Large Language Models (LLMs) to interpret images through visual instruction tuning have achieved significant success. However, existing visual instruction tuning methods only utilize image-language instruction data to align the language and image modalities, lacking a more fine-grained cross-modal alignment. In this paper, we propose Position-enhanced Visual Instruction Tuning (PVIT), which extends the functionality of MLLMs by integrating an additional region-level vision encoder. This integration promotes a more detailed comprehension of images for the MLLM. In addition, to efficiently achieve a fine-grained alignment between the vision modules and the LLM, we design multiple data generation strategies to construct an image-region-language instruction dataset. Finally, we present both quantitative experiments and qualitative analysis that demonstrate the superiority of the proposed model. Code and data will be released at https://github.com/PVIT-official/PVIT

    Signal Processing for Digital Beamforming FMCW SAR

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    According to the limitations of single channel Frequency Modulation Continuous Wave (FMCW) Synthetic Aperture Radar (SAR), Digital Beamforming (DBF) technology is introduced to improve system performance. Combined with multiple receive apertures, DBF FMCW SAR can obtain high resolution in low pulse repetition frequency, which can increase the processing gain and decrease the sampling frequency. The received signal model of DBF FMCW SAR is derived. The continuous antenna motion which is the main characteristic of FMCW SAR received signal is taken into account in the whole signal processing. The detailed imaging diagram of DBF FMCW SAR is given. A reference system is also demonstrated in the paper by comparing with a single channel FMCW SAR. The validity of the presented diagram is demonstrated with a point target simulation results

    microRNA-223 Deficiency Exacerbates Acute Inflammatory Response to Monosodium Urate Crystals by Targeting NLRP3

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    Objective: MicroRNAs were identified as master-switch molecules limiting acute inflammatory response. This study investigated the potential role of microRNA (miR)-223 in the mechanism of gout. Methods: Wild-type (WT) and miR-223 knock-out (KO) mice were used to evaluate the phenotypes of gout models. Inflammatory cytokines were measured in air pouch and peritoneal cavity lavage fluid. In addition to miR-223 level in gout patients, miR-223 and pro-inflammatory genes were examined in bone marrow-derived macrophages (BMDMs) from mice as well as peripheral blood mononuclear cells from healthy controls (HC) treated with monosodium urate (MSU) crystals in vitro. Results: MiR-223 was up-regulated in the early phase in BMDMs from WT mice after MSU challenge and decreased rapidly, and this was not observed in miR-223 KO mice in vitro. In addition, miR-223 was required for macrophages homeostasis. In comparison with WT mice in vivo, miR-223 deficiency exacerbated swelling index of MSU-induced inflammation in foot pad and ankle joint models. MiR-223 deficiency also markedly aggravated inflammatory cells infiltration and cytokines release including interleukin (IL)-1β, IL-6 and monocyte chemotactic protein-1 (MCP-1) in the air pouch and peritonitis models. In the in vitro experiments, miR-223 deficiency promoted the inflammatory response by targeting NLR family pyrin domain containing protein 3 (NLRP3). Besides, miR-223 level was down-regulated in gout patients and in HC exposed to MSU in vitro. Conclusion: MiR-223 was down-regulated in gout patients and miR-223 deficiency exacerbated inflammatory response in diverse murine models, suggesting that up-regulation of miR-223 could be a potential therapeutic strategy for alleviating gouty inflammation
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