5,575 research outputs found

    Non-local quantum effects in cosmology 1: Quantum memory, non-local FLRW equations and singularity avoidance

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    We discuss cosmological effects of the quantum loops of massless particles, which lead to temporal non-localities in the equations of motion governing the scale factor a(t). For the effects discussed here, loops cause the evolution of a(t) to depend on the memory of the curvature in the past with a weight that scales initially as 1/(t-t'). As one of our primary examples we discuss the situation with a large number of light particles, such that these effects occur in a region where gravity may still be treated classically. However, we also describe the effect of quantum graviton loops and the full set of Standard Model particles. We show that these effects decrease with time in an expanding phase, leading to classical behavior at late time. In a contracting phase, within our approximations the quantum results can lead to a bounce-like behavior at scales below the Planck mass, avoiding the singularities required classically by the Hawking-Penrose theorems. For conformally invariant fields, such as the Standard Model with a conformally coupled Higgs, this result is purely non-local and parameter independent.Comment: 18 pages, 13 figures - extra references added and minor wording change

    Regge behavior in effective field theory

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    We derive the Regge behavior for the forward scattering amplitude in scalar field theory using the method of regions. We find that the leading Regge behavior to all orders can be obtained. Regge physics emerges from a kinematic region that involves the overlap of several modes, so that a careful treatment of the overlap regions is important. The most consistent and efficient approach utilizes graphs containing collinear, anti-collinear and Glauber modes, or modes of SCET_GComment: 18 pages, 6 figure

    MRI brain classification using support vector machine

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    The field of medical imaging gains its importance with increase in the need of automated and efficient diagnosis in a short period of time. Other than that, medical image retrieval system is to provide a tool for radiologists to retrieve the images similar to query image in content. Magnetic resonance imaging (MRI) is an imaging technique that has played an important role in neuroscience research for studying brain images. Classification is an important part in retrieval system in order to distinguish between normal patients and those who have the possibility of having abnormalities or tumor. In this paper, we have obtained the feature related to MRI images using discrete wavelet transformation. An advanced kernel based techniques such as Support Vector Machine (SVM) for the classification of volume of MRI data as normal and abnormal will be deployed

    A physiologically inspired model for solving the cocktail party problem.

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    At a cocktail party, we can broadly monitor the entire acoustic scene to detect important cues (e.g., our names being called, or the fire alarm going off), or selectively listen to a target sound source (e.g., a conversation partner). It has recently been observed that individual neurons in the avian field L (analog to the mammalian auditory cortex) can display broad spatial tuning to single targets and selective tuning to a target embedded in spatially distributed sound mixtures. Here, we describe a model inspired by these experimental observations and apply it to process mixtures of human speech sentences. This processing is realized in the neural spiking domain. It converts binaural acoustic inputs into cortical spike trains using a multi-stage model composed of a cochlear filter-bank, a midbrain spatial-localization network, and a cortical network. The output spike trains of the cortical network are then converted back into an acoustic waveform, using a stimulus reconstruction technique. The intelligibility of the reconstructed output is quantified using an objective measure of speech intelligibility. We apply the algorithm to single and multi-talker speech to demonstrate that the physiologically inspired algorithm is able to achieve intelligible reconstruction of an "attended" target sentence embedded in two other non-attended masker sentences. The algorithm is also robust to masker level and displays performance trends comparable to humans. The ideas from this work may help improve the performance of hearing assistive devices (e.g., hearing aids and cochlear implants), speech-recognition technology, and computational algorithms for processing natural scenes cluttered with spatially distributed acoustic objects.R01 DC000100 - NIDCD NIH HHSPublished versio

    Tinjauan Pelayanan Prima (Studi Kasus : Restoran A&w Cabang Mampang Jakarta)

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    Pelayanan yang cepat pada Restoran A & W Cabang Mampang Jakarta belum optimal, tetapi keramahan dan kesopanan karyawan Restoran A & W Cabang Mampang Jakarta sangat memuaskan para konsumen, terbukti banyaknya para pelanggan yang merasa nyaman dalam memesan makanan maupun ketika berada di dalam Restoran A & W Cabang Mampang Jakarta.Tujuan dari penelitian ini adalah penulis ingin mengetahui bagaimana pelayanan prima yang dilakukan oleh Restoran A & W Cabang Mampang Jakarta. Metode penelitian yang penulis gunakan adalah dengan meneliti secara langsung ke lokasi Perusahaan, dengan menanyakan tentang apa saja pelayanan prima yang dilakukan oleh Restoran A & W Cabang Mampang Jakarta, Studi Pustaka (library research), dan sumber-sumber tertulis baik yang tercetak maupun media elektronik yang dapat membantu penulis dalam penelitian ini. Dari hasil penelitian ini dapat dikatakan bahwa pelayanan prima yang dilakukan oleh Restoran A & W Cabang Mampang Jakarta selama periode bulan April sampai dengan Mei 2016 sudah cukup memuaskan untuk para konsumen. Semoga Restoran A & W Cabang Mampang Jakarta dapat meningkatkan pelayanan prima yang telah dicapai
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