3,711 research outputs found

    Parameterization of a Convolutional Autoencoder for Reconstruction of Small Images

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    The following topics are dealt with: mobile robots; control system synthesis; learning (artificial intelligence); feature extraction; robot vision; autonomous aerial vehicles; feedback; feedforward neural nets; nonlinear control systems; multi-robot systems

    In-situ Noise Measurement and Analysis for the Motorcycle Muffler

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    Noise from the vehicles is one of the noise pollution to the environment. The noises emitted by the vehicles have to obey the requirement of regulation of maximum sound pressure level permitted for respective vehicles. In this study, the aim is to reduce the noise emitted from the motorcycle muffler. The noise emitted from the motorcycle muffler is analyzed and measured using a sound level meter. The average sound pressure level of the motorcycle muffler is determined in certain conditions. The sound pressure level is obtained from original motorcycle muffler, when it is under constant speed (10 km/hr, 20 km/hr, 30 km/hr) and under acceleration (in the scope of 0 km/hr to 30 km/hr). The study is continued by using a modified motorcycle muffler which contains sound absorptive materials. The absorptive materials chosen are glass wool, cotton and Styrofoam and they are taking turn to be placed into the motorcycle muffler to reduce the sound pressure level. Then the experiment is repeated. It is found that Styrofoam does not perform significantly in absorbing sound or noise in this study. Glass wool demonstrates relatively better sound energy absorption compared with cotton. In general, soft and porous materials are considered good performance in sound absorption. Denser materials are better at soundproofing or sound blocking. Therefore, glass wool with relatively higher density among the investigated absorptive materials in this study has the greatest sound absorption performance

    Predicting mobile network operators users m-payment intention

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    Purpose – This study aims to investigate the intention of using mobile payment (m-payment) services in Sarawak, Malaysia. Design/methodology/approach – A total of 194 online payment users were selected to respond to the structured questionnaire. The partial least squares-structural equation modelling (PLS-SEM) was used to analyse the data by assessing the measurement and model. Findings – Perceived usefulness(PU)and perceived ease of use mediated the relationship between perceived compatibility(PC) and the intention to use the mobile payment for mobile network operators’ services. Research limitations/implications – The analysis provides insights that PC is considered as a significant determinant for mobile payment of mobile network operators’ services. Practical implications – The operators can consider factors such as PC in the design of their mobile applications and the potential to expand them-payment services too theirs e-wallet such as Sarawak e-wallet. The model possesses medium prediction power, which suggests that other variables such as perceived security and personal innovativeness also can be used to predict the usage behavior of mobile payment for the mobile network services. Originality/value – The present study contributes to them-payment users’ behavior intention literature by investigating the mobile-based predictors of using m-payment technology in an emerging digital economy state in Sarawak, Malaysia. This study also extends the knowledge of technology acceptance model by introducing the mediation effect of PU and ease of use between the mobile-based predictors and m-payment intention

    Field Instruction Multiple Data

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    Fully homomorphic encryption~(FHE) has flourished since it was first constructed by Gentry~(STOC 2009). Single instruction multiple data~(SIMD) gave rise to efficient homomorphic operations on vectors in (Ftd)(\mathbb{F}_{t^d})^\ell, for prime tt. RLWE instantiated with cyclotomic polynomials of the form X2N+1X^{2^N}+1 dominate implementations of FHE due to highly efficient fast Fourier transformations. However, this choice yields very short SIMD plaintext vectors and high degree extension fields, e.g. 100\ell 100 for small primes~(t=3,5,t = 3, 5, \dots). In this work, we describe a method to encode more data on top of SIMD, \emph{Field Instruction Multiple Data}, applying reverse multiplication friendly embedding~(RMFE) to FHE. With RMFE, length-kk Ft\mathbb{F}_{t} vectors can be encoded into Ftd\mathbb{F}_{t^d} and multiplied once. The results have to be recoded~(decoded and then re-encoded) before further multiplications can be done. We introduce an FHE-specific technique to additionally evaluate arbitrary linear transformations on encoded vectors for free during the FHE recode operation. On top of that, we present two optimizations to unlock high degree extension fields with small tt for homomorphic computation: rr-fold RMFE, which allows products of up to 2r2^r encoded vectors before recoding, and a three-stage recode process for RMFEs obtained by composing two smaller RMFEs. Experiments were performed to evaluate the effectiveness of FIMD from various RMFEs compared to standard SIMD operations. Overall, we found that FIMD generally had >2×>2\times better (amortized) multiplication times compared to FHE for the same amount of data, while using almost k/2×k/2 \times fewer ciphertexts required

    Macrophage IL-1β contributes to tumorigenesis through paracrine AIM2 inflammasome activation in the tumor microenvironment

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    Intracellular recognition of self and non-self -nucleic acids can result in the initiation of effective pro-inflammatory and anti-tumorigenic responses. We hypothesized that macrophages can be activated by tumor-derived nucleic acids to induce inflammasome activation in the tumor microenvironment. We show that tumor conditioned media (CM) can induce IL-1β production, indicative of inflammasome activation in primed macrophages. This could be partially dependent on caspase 1/11, AIM2 and NLRP3. IL-1β enhances tumor cell proliferation, migration and invasion while coculture of tumor cells with macrophages enhances the proliferation of tumor cells, which is AIM2 and caspase 1/11 dependent. Furthermore, we have identified that DNA-RNA hybrids could be the nucleic acid form which activates AIM2 inflammasome at a higher sensitivity as compared to dsDNA. Taken together, the tumor-secretome stimulates an innate immune pathway in macrophages which promotes paracrine cancer growth and may be a key tumorigenic pathway in cancer. Broader understanding on the mechanisms of nucleic acid recognition and interaction with innate immune signaling pathway will help us to better appreciate its potential application in diagnostic and therapeutic benefit in cancer

    Systematic Identification of Factors for Provirus Silencing in Embryonic Stem Cells

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    Embryonic stem cells (ESCs) repress the expression of exogenous proviruses and endogenous retroviruses (ERVs). Here, we systematically dissected the cellular factors involved in provirus repression in embryonic carcinomas (ECs) and ESCs by a genome-wide siRNA screen. Histone chaperones (Chaf1a/b), sumoylation factors (Sumo2/Ube2i/Sae1/Uba2/Senp6), and chromatin modifiers (Trim28/Eset/Atf7ip) are key determinants that establish provirus silencing. RNA-seq analysis uncovered the roles of Chaf1a/b and sumoylation modifiers in the repression of ERVs. ChIP-seq analysis demonstrates direct recruitment of Chaf1a and Sumo2 to ERVs. Chaf1a reinforces transcriptional repression via its interaction with members of the NuRD complex (Kdm1a, Hdac1/2) and Eset, while Sumo2 orchestrates the provirus repressive function of the canonical Zfp809/Trim28/Eset machinery by sumoylation of Trim28. Our study reports a genome-wide atlas of functional nodes that mediate proviral silencing in ESCs and illuminates the comprehensive, interconnected, and multi-layered genetic and epigenetic mechanisms by which ESCs repress retroviruses within the genome

    Co-transplantation of Human Embryonic Stem Cell-derived Neural Progenitors and Schwann Cells in a Rat Spinal Cord Contusion Injury Model Elicits a Distinct Neurogenesis and Functional Recovery

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    Co-transplantation of neural progenitors (NPs) with Schwann cells (SCs) might be a way to overcome low rate of neuronal differentiation of NPs following transplantation in spinal cord injury (SCI) and the improvement of locomotor recovery. In this study, we initially generated NPs from human embryonic stem cells (hESCs) and investigated their potential for neuronal differentiation and functional recovery when co-cultured with SCs in vitro and co-transplanted in a rat acute model of contused SCI. Co-cultivation results revealed that the presence of SCs provided a consistent status for hESC-NPs and recharged their neural differentiation toward a predominantly neuronal fate. Following transplantation, a significant functional recovery was observed in all engrafted groups (NPs, SCs, NPs+SCs) relative to the vehicle and control groups. We also observed that animals receiving co-transplants established a better state as assessed with the BBB functional test. Immunohistofluorescence evaluation five weeks after transplantation showed invigorated neuronal differentiation and limited proliferation in the co-transplanted group when compared to the individual hESC-NPs grafted group. These findings have demonstrated that the co-transplantation of SCs with hESC-NPs could offer a synergistic effect, promoting neuronal differentiation and functional recovery

    The Kalanchoe genome provides insights into convergent evolution and building blocks of crassulacean acid metabolism

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    Crassulacean acid metabolism (CAM) is a water-use efficient adaptation of photosynthesis that has evolved independently many times in diverse lineages of flowering plants. We hypothesize that convergent evolution of protein sequence and temporal gene expression underpins the independent emergences of CAM from C3 photosynthesis. To test this hypothesis, we generate a de novo genome assembly and genome-wide transcript expression data for Kalanchoë fedtschenkoi, an obligate CAM species within the core eudicots with a relatively small genome (~260 Mb). Our comparative analyses identify signatures of convergence in protein sequence and re-scheduling of diel transcript expression of genes involved in nocturnal CO2 fixation, stomatal movement, heat tolerance, circadian clock, and carbohydrate metabolism in K. fedtschenkoi and other CAM species in comparison with non-CAM species. These findings provide new insights into molecular convergence and building blocks of CAM and will facilitate CAM-into-C3 photosynthesis engineering to enhance water-use efficiency in crops

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum
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