118 research outputs found

    Efficient Neural Network Robustness Certification with General Activation Functions

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    Finding minimum distortion of adversarial examples and thus certifying robustness in neural network classifiers for given data points is known to be a challenging problem. Nevertheless, recently it has been shown to be possible to give a non-trivial certified lower bound of minimum adversarial distortion, and some recent progress has been made towards this direction by exploiting the piece-wise linear nature of ReLU activations. However, a generic robustness certification for general activation functions still remains largely unexplored. To address this issue, in this paper we introduce CROWN, a general framework to certify robustness of neural networks with general activation functions for given input data points. The novelty in our algorithm consists of bounding a given activation function with linear and quadratic functions, hence allowing it to tackle general activation functions including but not limited to four popular choices: ReLU, tanh, sigmoid and arctan. In addition, we facilitate the search for a tighter certified lower bound by adaptively selecting appropriate surrogates for each neuron activation. Experimental results show that CROWN on ReLU networks can notably improve the certified lower bounds compared to the current state-of-the-art algorithm Fast-Lin, while having comparable computational efficiency. Furthermore, CROWN also demonstrates its effectiveness and flexibility on networks with general activation functions, including tanh, sigmoid and arctan.Comment: Accepted by NIPS 2018. Huan Zhang and Tsui-Wei Weng contributed equall

    Traditional Chinese medicine in patients with osteoarthritis of the knee

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    AbstractTo evaluate whether the use of traditional Chinese medicine (TCM; 中醫 zhōng yī) influences symptoms or functional outcomes in patients with osteoarthritis (OA) of the knee (膝關節炎 xī guān jié yán).A systematic review of randomized control trials was conducted. Searches for studies in PubMed that were performed between 1965 and August 2013, and retrieved studies were subjected to reference screening. The types of studies included in our review were 1) placebo-based or comparative studies; 2) open label, single-blinded or double-blinded studies; 3) studies evaluating the efficacy of TCM for treating OA of the knee; and 4) studies evaluating only TCM or combination preparations. Trials were conducted with participants over 18 years of age with knee pain and at least three of the following characteristics: 1) an age greater than 50 years; 2) morning stiffness lasting for fewer than 30 min; 3) a crackling or grating sensation; 4) bony tenderness of the knee; 5) bony enlargement of the knee; or 6) no detectable warmth of the joint to the touch. Studies were rated for risk of bias and graded for quality.After screening, 104 studies that satisfied the eligibility requirements were identified, and only 18 randomized control trials were included in the quantitative and qualitative synthesis. Upon review, we found “moderate-quality” evidence of effects from acupuncture (針灸 zhēn jiǔ) on pain, which was measured using a visual analogue scale, and physical function, which was measured using qigong (氣功 qì gōng) with motion. “Low-quality” evidence was found regarding the effects of acupuncture on physical function, and no evidence was found regarding the effects of herbal medicine on pain or physical function. Herbal patches (藥布 yào bù) appeared to affect pain and physical and function, but these effects were not found to be significant.The initial findings included in this review suggest that acupuncture is a promising intervention according to the primary outcome measure, pain, and qigong with motion is an effective method for treating physical function. However, according to the Grades of Recommendation, Assessment, Development, and Evaluation criteria, only moderate-quality evidence was found in these studies. Further rigorous studies are warranted to investigate the application of TCM in treating OA of knee

    Fabrication of Inorganic Coatings Incorporated with Functionalized Graphene Oxide Nanosheets for Improving Fire Retardancy of Wooden Substrates

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    Flame-retardant chemicals are frequently used within consumer products and can even be employed as a treatment on the surface of different types of materials (e.g., wood, steel, and textiles) to prevent fire or limit the rapid spread of flames. Functionalized graphene oxide (FGO) nanosheets are a promising construction coating nanomaterial that can be blended with sodium metasilicate and gypsum to reduce the flammability of construction buildings. In this work, we designed and fabricated novel and halogen-free FGO sheets using the modified Hummers method; and subsequently functionalized them by pentaerythritol through a chemical impregnation process before dispersing them within the construction coating. Scanning electron microscopic images confirm that the FGO-filled coating was uniformly dispersed on the surface of wooden substrates. We identified that the FGO content is a critical factor affecting the fire retardancy. Thermogravimetric analysis of the FGO coating revealed that higher char residue can be obtained at 700 °C. Based on the differential scanning calorimetry, the exothermic peak contained a temperature delay in the presence of FGO sheets, primarily due to the formation of a thermal barrier. Such a significant improvement in the flame retardancy confirms that the FGO nanosheets are superior nanomaterials to be employed as a flame-retardant construction coating nanomaterial for improving thermal management within buildings

    Association of ORAI1 Haplotypes with the Risk of HLA-B27 Positive Ankylosing Spondylitis

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    Ankylosing spondylitis (AS) is a chronic inflammation of the sacroiliac joints, spine and peripheral joints. The aetiology of ankylosing spondylitis is still unclear. Previous studies have indicated that genetics factors such as human leukocyte antigen HLA-B27 associates to AS susceptibility. We carried out a case-control study to determine whether the genetic polymorphisms of ORAI1 gene, a major component of store-operated calcium channels that involved the regulation of immune system, is a susceptibility factor to AS in a Taiwanese population. We enrolled 361 AS patients fulfilled the modified New York criteria and 379 controls from community. Five tagging single nucleotides polymorphisms (tSNPs) at ORAI1 were selected from the data of Han Chinese population in HapMap project. Clinical statuses of AS were assessed by the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI), and Bath Ankylosing Spondylitis Global Index (BAS-G). Our results indicated that subjects carrying the minor allele homozygote (CC) of the promoter SNP rs12313273 or TT homozygote of the SNP rs7135617 had an increased risk of HLA-B27 positive AS. The minor allele C of 3′UTR SNP rs712853 exerted a protective effect to HLA-B27 positive AS. Furthermore, the rs12313273/rs7135617 pairwise allele analysis found that C-G (OR 1.69, 95% CI 1.27, 2.25; p = 0.0003) and T-T (OR 1.75, 95% CI 1.36, 2.27; p<0.0001) haplotypes had a significantly association with the risk of HLA-B27-positive AS in comparison with the T-G carriers. This is the first study that indicate haplotypes of ORAI1 (rs12313273 and rs7135617) are associated with the risk of HLA-B27 positive AS

    Levitation by a dipole electric field

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    The phenomenon of floating can be fascinating in any field, with its presence seen in art, films, and scientific research. This phenomenon is a captivating and pertinent subject with practical applications, such as Penning traps for antimatter confinement and Ion traps as essential architectures for quantum computing models. In our project, we reproduced the 1893 water bridge experiment using glycerol and first observed that lump-like macroscopic dipole moments can undergo near-periodic oscillations that exhibit floating effects and do not need classical bridge form. By combining experimental analysis, neural networks, investigation of Kelvin force generated by the Finite element method, and exploration of discharging, we gain insights into the mechanisms of motion. Our discovery has overturned the previous impression of a bridge floating in the water, leading to a deeper understanding of the new trap mechanism under strong electric fields with a single pair of electrodes.Comment: 5 pages, 5 figure

    Preparation of SiO2-Protecting Metallic Fe Nanoparticle/SiO2 Composite Spheres for Biomedical Application

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    Functionalized Fe nanoparticles (NPs) have played an important role in biomedical applications. In this study, metallic Fe NPs were deposited on SiO2 spheres to form a Fe/SiO2 composite. To protect the Fe from oxidation, a thin SiO2 layer was coated on the Fe/SiO2 spheres thereafter. The size and morphology of the SiO2@Fe/SiO2 composite spheres were examined by transmission electron microscopy (TEM). The iron form and its content and magnetic properties were examined by X-ray diffraction (XRD), inductively-coupled plasma mass spectrometry (ICP-MS) and a superconducting quantum interference device (SQUID). The biocompatibility of the SiO2@Fe/SiO2 composite spheres was examined by Cell Counting Kit-8 (CCK-8) and lactate dehydrogenase (LDH) tests. The intracellular distribution of the SiO2@Fe/SiO2 composite spheres was observed using TEM. XRD analysis revealed the formation of metallic iron on the surface of the SiO2 spheres. According to the ICP-MS and SQUID results, using 0.375 M FeCl3·6H2O for Fe NPs synthesis resulted in the highest iron content and magnetization of the SiO2@Fe/SiO2 spheres. Using a dye loading experiment, a slow release of a fluorescence dye from SiO2@Fe/SiO2 composite spheres was confirmed. The SiO2@Fe/SiO2 composite spheres co-cultured with L929 cells exhibit biocompatibility at concentrations &lt;16.25 µg/mL. The TEM images show that the SiO2@Fe/SiO2 composite spheres were uptaken into the cytoplasm and retained in the endosome. The above results demonstrate that the SiO2@Fe/SiO2 composite spheres could be used as a multi-functional agent, such as a magnetic resonance imaging (MRI) contrast agent or drug carriers in biomedical applications

    Efficient Identification of Hot Data for Flash-Memory Storage Systems

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    Hot-data identification for flash-memory storage systems not only imposes great impacts on flash-memory garbage collection but also strongly affects the performance of flash-memory access and its life time (due to wear-levelling). This research proposes a highly efficient method for on-line hot-data identification with limited space requirements. Different from the past work, multiple independent hash functions are adopted to reduce the chance of false identification of hot data and to provide predictable and excellent performance for hot-data identification. This research not only offers an efficient implementation for the proposed framework but also presents an analytic study on the chance of false hot-data identification. A series of experiments was conducted to verify the performance of the proposed method, in which very encouraging results are presented
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