2,109 research outputs found

    Water Saturation and Porosity Prediction Using Back-propagation Artificial Neural Network (BPANN) from Well Log Data

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    Porosity and water saturation are two fundamental parameters in reservoir characterization. In this study, for predicting both mentioned parameters artificial neural network was used as intelligent technique.  Five variables include neutron log, effective porosity, caliper log, bulk density, and sonic log were used from 3 wells from one of the Iranian oil fields. After normalizing data Seventy percent of data were used as training dataset and remainder for testing the network. Several feed –forward neural networks were operated to obtain best performance of different algorithms to train the network. Levenberge-Marquardt back-propagation algorithm was chosen as the training algorithm which had the best performance and was faster than other algorithms. Optimum neurons in the hidden layer for porosity and water saturation were obtained respectively. Results shown that Backpropagation artificial neural network (BPANN) has a high ability to predict porosity and water saturation which correlation between real output and predicted output using BPANN were 0.82 and 0.93 respectively

    Development of a Voice Virtual Assistant for the Geospatial Data Visualization Application on the Web

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    Voice assistants can elevate interaction in geospatial data web platforms. This research introduces a voice assistant in the BStreams platform and focuses on understanding user commands in the geospatial domain. We developed a specialised geospatial discourse framework through structured prototyping. A survey with 66 participants revealed prevalent English geospatial terminologies. Using ChatGPT, we found the term suggestions aligned with survey results, with a notable correlation (r = 0.81, p < 0.01) between the NPL model’s probability scores and term prevalence in survey data. Our study also incorporated usability tests on the application, which uses tools like Web Speech API, Leaflet, and Mapbox geocoding. Results from these tests reaffirm the potential of voice assistants in enhancing geospatial data visualisation, though challenges persist in areas like language understanding and domain knowledge. The paper advocates for further research to refine the integration of voice technology in this domain

    Decaying DC offset current mitigation in phasor estimation applications: A Review

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    Decaying DC (DDC) offset current mitigation is a vital challenge in phasor current estimation since it causes malfunctioning/maloperation of measurements and protection systems. Due to the inductive nature of electric power systems, the current during fault inception cannot change immediately and it contains a transient oscillation. The oscillatory component acts similar to an exponential DC signal and its characteristics depend on the X/R ratio of the system, fault location, and fault impedance. DDC attenuates accurate phasor estimation, which is pivotal in protection systems. Therefore, the DDC must be eliminated from the fault current (FC) signal. This paper presents an overview of DDC mitigation methods by considering different groups—before the discrete Fourier transform (pre-DFT), after the discrete Fourier transform (post-DFT), the least square-based (LS-based), and other methods. Through a comprehensive review of the existing schemes, the effects of noise, harmonics, multiple DDCs (MDDCs), and off-nominal frequency (ONF) on the accuracy of DDC estimation, were recognized. A detailed discussion (along with some simulation results) are presented to address the main advantages/disadvantages of the past studies. Finally, this paper presents a few suggestions for future researchers, for researchers to investigate more implementable solutions in this field

    Group velocity control in the ultraviolet domain via interacting dark-state resonances

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    The propagation of a weak probe field in a laser-driven four-level atomic system is investigated. We choose mercury as our model system, where the probe transition is in the ultraviolet region. A high-resolution peak appears in the optical spectra due to the presence of interacting dark resonances. We show that this narrow peak leads to superluminal light propagation with strong absorption, and thus by itself is only of limited interest. But if in addition a weak incoherent pump field is applied to the probe transition, then the peak structure can be changed such that both sub- and superluminal light propagation or a negative group velocity can be achieved without absorption, controlled by the incoherent pumping strength

    Epidemiology of oral cancer in Iran: A systematic review

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    Background: Oral cancer stands among the 10 top causes of cancer death in the world. Considering the role of epidemiologic information on planning and effective interventions, the present study aimed to investigate the epidemiology of oral cancer in Iran. Materials and Methods: The required information for this systematic review study was obtained from PubMed, Google Scholar, CINAHL,SID, Medlib, Magiran and Iranmedex databases, using key words "cancer", "oral cancer", "squamous cell carcinoma", "oral cavity carcinoma" and their Persian equivalents in combination with keywords of epidemiology, prevalence, etiology, frequency, and Iran from 1990 to 2014. From 1,065 related studies found, finally 25 were included to the study. Results: The mean age of 8,248 patients in 25 studies was 54.0±15.1 years. The male/female ratio for oral cancer was 1.91. Tongue with average percentage of 29.9 was the most involved site. Regarding microscopic grade, 65.7 of cases were grade 1. SCCs, accounting for an average of 70.0, was the most common among all types of oral cancer. In the majority of studies, smoking including cigarette, hookah, and tobacco consumption was found to be a risk factor. Conclusions: The epidemiological pattern of oral cancer in Iran is somewhat similar to that of other countries. Yet the information on hand in this field is limited and considering the role of epidemiological data we suggest conducting more accurate studies to catch data that is required for effective programs and interventions

    The decay Bs -> mu+ mu-: updated SUSY constraints and prospects

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    We perform a study of the impact of the recently released limits on BR(Bs -> mu+ mu-) by LHCb and CMS on several SUSY models. We show that the obtained constraints can be superior to those which are derived from direct searches for SUSY particles in some scenarios, and the use of a double ratio of purely leptonic decays involving Bs -> mu+ mu- can further strengthen such constraints. We also discuss the experimental sensitivity and prospects for observation of Bs -> mu+ mu- during the sqrt(s)=7 TeV run of the LHC, and its potential implications.Comment: 30 pages, 21 figures. v2: Improved discussion of constraints from B -> tau nu, references adde

    Hydrodynamic instabilities in gaseous detonations: comparison of Euler, Navier–Stokes, and large-eddy simulation

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    A large-eddy simulation is conducted to investigate the transient structure of an unstable detonation wave in two dimensions and the evolution of intrinsic hydrodynamic instabilities. The dependency of the detonation structure on the grid resolution is investigated, and the structures obtained by large-eddy simulation are compared with the predictions from solving the Euler and Navier–Stokes equations directly. The results indicate that to predict irregular detonation structures in agreement with experimental observations the vorticity generation and dissipation in small scale structures should be taken into account. Thus, large-eddy simulation with high grid resolution is required. In a low grid resolution scenario, in which numerical diffusion dominates, the structures obtained by solving the Euler or Navier–Stokes equations and large-eddy simulation are qualitatively similar. When high grid resolution is employed, the detonation structures obtained by solving the Euler or Navier–Stokes equations directly are roughly similar yet equally in disagreement with the experimental results. For high grid resolution, only the large-eddy simulation predicts detonation substructures correctly, a fact that is attributed to the increased dissipation provided by the subgrid scale model. Specific to the investigated configuration, major differences are observed in the occurrence of unreacted gas pockets in the high-resolution Euler and Navier–Stokes computations, which appear to be fully combusted when large-eddy simulation is employed

    Autosomal recessive congenital ichthyosis: CERS3 mutations identified by a next generation sequencing panel targeting ichthyosis genes

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    There are at least 38 mutant genes known to be associated with the ichthyosis phenotypes, and autosomal recessive congenital ichthyosis (ARCI) is a specific subgroup caused by mutations in 13 different genes. Mutations in some of these genes, such as CERS3 with only two previous reports, are rare. In this study, we identified mutations in candidate genes in consanguineous families with ARCI with a next generation sequencing (NGS) array that incorporates 38 ichthyosis associated genes. We applied this sequencing array to DNA from 140 ichthyosis families with high prevalence of consanguinity. Among these patients we identified six distinct, previously unreported mutations in CERS3 in six Iranian families. These mutations in each family co-segregated with the ichthyosis phenotype. The patients demonstrated collodion membrane at birth, acrogeria, generalized scaling, and hyperlinearity of the palms and soles. The presence of a significant percentage of CERS3 mutations in our cohort depicts a marked difference between the etiology of ichthyoses in genetically poorly characterized regions and well-characterized western populations. Also, it shows that rare alleles are more prevalent in the gene pool of consanguineous populations and emphasizes the importance of these population studies for better understanding of ichthyosis pathogenesis

    The Higgs sector of the phenomenological MSSM in the light of the Higgs boson discovery

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    The long awaited discovery of a new light scalar at the LHC opens up a new era of studies of the Higgs sector in the SM and its extensions. In this paper we discuss the consequences of the observation of a light Higgs boson with the mass and rates reported by the ATLAS and CMS collaborations on the parameter space of the phenomenological MSSM, including also the so far unsuccessful LHC searches for the heavier Higgs bosons and supersymmetric particle partners in missing transverse momentum as well as the constraints from B physics and dark matter. We explore the various regimes of the MSSM Higgs sector depending on the parameters MA and tan beta and show that only two of them are still allowed by all present experimental constraints: the decoupling regime where there is only one light and standard--like Higgs boson and the supersymmetric regime in which there are light supersymmetric particle partners affecting the decay properties of the Higgs boson, in particular its di-photon and invisible decays.Comment: 21 pages, 9 figures v2 - Discussion of the impact of LHC data extended, scan statistics increased, a few figures added and typos correcte
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