5,025 research outputs found

    TV News Story Segmentation Based on Semantic Coherence and Content Similarity

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    In this paper, we introduce and evaluate two novel approaches, one using video stream and the other using close-caption text stream, for segmenting TV news into stories. The segmentation of the video stream into stories is achieved by detecting anchor person shots and the text stream is segmented into stories using a Latent Dirichlet Allocation (LDA) based approach. The benefit of the proposed LDA based approach is that along with the story segmentation it also provides the topic distribution associated with each segment. We evaluated our techniques on the TRECVid 2003 benchmark database and found that though the individual systems give comparable results, a combination of the outputs of the two systems gives a significant improvement over the performance of the individual systems

    Photon-Efficient Computational 3D and Reflectivity Imaging with Single-Photon Detectors

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    Capturing depth and reflectivity images at low light levels from active illumination of a scene has wide-ranging applications. Conventionally, even with single-photon detectors, hundreds of photon detections are needed at each pixel to mitigate Poisson noise. We develop a robust method for estimating depth and reflectivity using on the order of 1 detected photon per pixel averaged over the scene. Our computational imager combines physically accurate single-photon counting statistics with exploitation of the spatial correlations present in real-world reflectivity and 3D structure. Experiments conducted in the presence of strong background light demonstrate that our computational imager is able to accurately recover scene depth and reflectivity, while traditional maximum-likelihood based imaging methods lead to estimates that are highly noisy. Our framework increases photon efficiency 100-fold over traditional processing and also improves, somewhat, upon first-photon imaging under a total acquisition time constraint in raster-scanned operation. Thus our new imager will be useful for rapid, low-power, and noise-tolerant active optical imaging, and its fixed dwell time will facilitate parallelization through use of a detector array.Comment: 11 pages, 8 figure

    Computational multi-depth single-photon imaging

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    We present an imaging framework that is able to accurately reconstruct multiple depths at individual pixels from single-photon observations. Our active imaging method models the single-photon detection statistics from multiple reflectors within a pixel, and it also exploits the fact that a multi-depth profile at each pixel can be expressed as a sparse signal. We interpret the multi-depth reconstruction problem as a sparse deconvolution problem using single-photon observations, create a convex problem through discretization and relaxation, and use a modified iterative shrinkage-thresholding algorithm to efficiently solve for the optimal multi-depth solution. We experimentally demonstrate that the proposed framework is able to accurately reconstruct the depth features of an object that is behind a partially-reflecting scatterer and 4 m away from the imager with root mean-square error of 11 cm, using only 19 signal photon detections per pixel in the presence of moderate background light. In terms of root mean-square error, this is a factor of 4.2 improvement over the conventional method of Gaussian-mixture fitting for multi-depth recovery.This material is based upon work supported in part by a Samsung Scholarship, the US National Science Foundation under Grant No. 1422034, and the MIT Lincoln Laboratory Advanced Concepts Committee. We thank Dheera Venkatraman for his assistance with the experiments. (Samsung Scholarship; 1422034 - US National Science Foundation; MIT Lincoln Laboratory Advanced Concepts Committee)Accepted manuscrip

    Orbital order of spinless fermions near an optical Feshbach resonance

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    We study the quantum phases of a three-color Hubbard model that arises in the dynamics of the p-band orbitals of spinless fermions in an optical lattice. Strong, color-dependent interactions are induced by an optical Feshbach resonance. Starting from the microscopic scattering properties of ultracold atoms, we derive the orbital exchange constants at 1/3 filling on the cubic optical lattice. Using this, we compute the phase diagram in a Gutzwiller ansatz. We find novel phases with 'axial orbital order' in which pz and px + ipy (or px - ipy) orbitals alternate.Comment: 4+epsilon pages, 3 figures. Similar to version published in PRA(R

    Establishment of an efficient protocol for micropropagation of stem explants of Tylophora indica, an important medicinal plant

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    An efficient reproducible protocol has been developed for in vitro propagation of endangered medicinal plant (Tylophora indica). The concentration of plant growth regulators and explant types exhibited discrete roles in the efficiency of plant regeneration. Stem explants cultured on 8.8 μM 6- benzylaminopurine (BAP) resulted in formation of nodular meristemoids, which developed into green leafy shoots 6 to 8 weeks after culturing on the same medium. 29.4 μM α-naphthalene acetic acid (NAA) and 4.65 μM kinetin (Kn) induced green solid callus within 7 to 8 days of culturing. Callus thus formed, revealed the presence of cells of variable shapes and sizes together with xylogenesis. Calli when subcultured on MS medium supplemented with 8.8 μM BAP developed adventitious shoots, however, initially, few shoots were formed but the number increased further on subsequent subculturing. Microshoots thus formed, were cultured on indole 3-butyric acid (IBA) and half strength basal MS media for induction of roots. Regenerated plantlets with healthy shoots and roots were acclimatized in moist cotton followed by their hardening in soil : vermicompost potting mixture with 90% survival rate.Key words: Tylophora indica, organogenesis, 6-benzylaminopurine, α-naphthalene acetic acid, indole 3- butyric acid

    Evaluation of anxiolytic effect of furosemide in Albino rats

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    Background: Anxiety disorders are the most prevalent class of psychiatric condition. Medications commonly given for treatment can elicit several central nervous system (CNS) side-effects that patients find difficult to tolerate. So there is a need for new pharmacotherapeutic approaches to treat anxiety with greater efficacy and fewer side effects. Hence this study has been taken up to evaluate the anxiolytic effect of furosemide at three different doses (75mg/kg, 150mg/kg and 200mg/kg) in Albino rats.Methods: After obtaining approval from the institutional animal ethical committee 30 Albino rats weighing about 150-200gm were taken and divided into 5 groups of 6 rats each. Group 1: Normal Saline 10ml/kg (control); Group 2: Diazepam 2mg/kg (standard); Group 3: Furosemide 150mg/kg (test group 1); Group 4: Furosemide 200mg/kg (test group 2); Group 5: Furosemide 75mg/kg + Diazepam 1mg/kg (sub threshold dose). The anxiolytic activity of furosemide was tested by elevated plus maze and digital actophotometer models. Data was analysed using one way ANOVA followed by Posthoc Tukey’s test.Results: Furosemide (150mg/kg and 200mg/kg) have shown significant increase in open arm entries (p<0.05) and time spent in open arm (p<0.05) compared to control. Also furosemide (150mg/kg and 200mg/kg) have shown statistically significant decrease in locomotor activity (p<0.05) compared to control in actophotometer model. Potentiation of time spent and number of entries in open arm and decrease in locomotor activity were noticed when sub threshold doses of combination of diazepam and furosemide were used.Conclusions: These results suggest that furosemide possesses significant anxiolytic activity at both the doses. Furosemide given in sub threshold dose potentiates the antianxiety effect of sub threshold dose of diazepam when used in combination. Hence, after further studies, furosemide can be used as an anxiolytic drug
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