6,539 research outputs found
Cutting the Error by Half: Investigation of Very Deep CNN and Advanced Training Strategies for Document Image Classification
We present an exhaustive investigation of recent Deep Learning architectures,
algorithms, and strategies for the task of document image classification to
finally reduce the error by more than half. Existing approaches, such as the
DeepDocClassifier, apply standard Convolutional Network architectures with
transfer learning from the object recognition domain. The contribution of the
paper is threefold: First, it investigates recently introduced very deep neural
network architectures (GoogLeNet, VGG, ResNet) using transfer learning (from
real images). Second, it proposes transfer learning from a huge set of document
images, i.e. 400,000 documents. Third, it analyzes the impact of the amount of
training data (document images) and other parameters to the classification
abilities. We use two datasets, the Tobacco-3482 and the large-scale RVL-CDIP
dataset. We achieve an accuracy of 91.13% for the Tobacco-3482 dataset while
earlier approaches reach only 77.6%. Thus, a relative error reduction of more
than 60% is achieved. For the large dataset RVL-CDIP, an accuracy of 90.97% is
achieved, corresponding to a relative error reduction of 11.5%
Structural insights into RNA processing by the human RISC-loading complex.
Targeted gene silencing by RNA interference (RNAi) requires loading of a short guide RNA (small interfering RNA (siRNA) or microRNA (miRNA)) onto an Argonaute protein to form the functional center of an RNA-induced silencing complex (RISC). In humans, Argonaute2 (AGO2) assembles with the guide RNA-generating enzyme Dicer and the RNA-binding protein TRBP to form a RISC-loading complex (RLC), which is necessary for efficient transfer of nascent siRNAs and miRNAs from Dicer to AGO2. Here, using single-particle EM analysis, we show that human Dicer has an L-shaped structure. The RLC Dicer's N-terminal DExH/D domain, located in a short 'base branch', interacts with TRBP, whereas its C-terminal catalytic domains in the main body are proximal to AGO2. A model generated by docking the available atomic structures of Dicer and Argonaute homologs into the RLC reconstruction suggests a mechanism for siRNA transfer from Dicer to AGO2
Topological Polaritons in a Quantum Spin Hall Cavity
We study the topological structure of matter-light excitations, so called
polaritons, in a quantum spin Hall insulator coupled to photonic cavity modes.
We identify a topological invariant in the presence of time reversal (TR)
symmetry, and demonstrate the existence of a TR-invariant topological phase. We
find protected helical edge states with energies below the lower polariton
branch and characteristic uncoupled excitonic states, both detectable by
optical techniques. Applying a Zeeman field allows us to relate the topological
index to the double coverage of the Bloch sphere by the polaritonic pseudospin.Comment: 5 pages + 4 pages supplemental material, 3 figure
A Survey of Digital Systems Curriculum and Pedagogy in Electrical and Computer Engineering Programs
Digital Systems is one of the basic foundational courses in Electrical and Computer Engineering. One of the challenges in designing and modifying the curriculum for the course is the fast pace of technology change in the area. TTL chips that were in vogue with students building physical circuits, have given way to new paradigms like FPGA based synthesis with hardware description languages such as VHDL. However, updating a course is not as simple as just changing the book, and changing the syllabus. A large amount of work needs to be done in terms of selecting the book that will accommodate the course, the device that should be used, the laboratory content, and even how much time needs to be dedicated for every topic. All these issues, and many more makes it hard to take the decision of updating the course. For that reason, this paper surveys the pedagogy and methodology that is used to teach the digital systems curriculum at different universities. The goal is that it will serve as a resource for faculty looking to update or revamp their digital systems curricula. Within the document they will find a comparative study by electrical and computer engineering program, a list of textbooks, and the devices most commonly used.Cockrell School of Engineerin
Modelling a single phase voltage controlled rectifier using Laplace transforms
The development of a 20 kHz, AC power system by NASA for large space projects has spurred a need to develop models for the equipment which will be used on these single phase systems. To date, models for the AC source (i.e., inverters) have been developed. It is the intent of this paper to develop a method to model the single phase voltage controlled rectifiers which will be attached to the AC power grid as an interface for connected loads. A modified version of EPRI's HARMFLO program is used as the shell for these models. The results obtained from the model developed in this paper are quite adequate for the analysis of problems such as voltage resonance. The unique technique presented in this paper uses the Laplace transforms to determine the harmonic content of the load current of the rectifier rather than a curve fitting technique. Laplace transforms yield the coefficient of the differential equations which model the line current to the rectifier directly
The adsorption of sulfur by microporous materials
The sorption of sulfur by the zeolites NaX (= 13X) and CaA (= 5A) and an activated charcoal prepared from sugar was investigated at temperatures between 150 and 350°C and relative sulfur pressures between 10−4 and 10−1. The adsorbate-adsorbate interaction indicated by the S-shaped isotherm for the zeolite NaX points to physical or chemical interaction of sulfur molecules in neighboring supercages. In CaA adsorbate-adsorbate interaction between sulfur species in different supercages is negligible. Below 200°C the rate of sulfur uptake by the zeolite CaA is determined by the diffusion rate of a sulfur species through the zeolitic framework. In activated charcoal a strong adsorbate-adsorbent interaction is present and part of the sulfur is chemisorbed at 350°C. The differences in the density of the adsorbed sulfur determined with three different methods indicate that even at full saturation of the micropore volume with sulfur, there is still some residual adsorption volume
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