2,965 research outputs found

    Weakly Supervised Localization using Deep Feature Maps

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    Object localization is an important computer vision problem with a variety of applications. The lack of large scale object-level annotations and the relative abundance of image-level labels makes a compelling case for weak supervision in the object localization task. Deep Convolutional Neural Networks are a class of state-of-the-art methods for the related problem of object recognition. In this paper, we describe a novel object localization algorithm which uses classification networks trained on only image labels. This weakly supervised method leverages local spatial and semantic patterns captured in the convolutional layers of classification networks. We propose an efficient beam search based approach to detect and localize multiple objects in images. The proposed method significantly outperforms the state-of-the-art in standard object localization data-sets with a 8 point increase in mAP scores

    Search Tracker: Human-derived object tracking in-the-wild through large-scale search and retrieval

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    Humans use context and scene knowledge to easily localize moving objects in conditions of complex illumination changes, scene clutter and occlusions. In this paper, we present a method to leverage human knowledge in the form of annotated video libraries in a novel search and retrieval based setting to track objects in unseen video sequences. For every video sequence, a document that represents motion information is generated. Documents of the unseen video are queried against the library at multiple scales to find videos with similar motion characteristics. This provides us with coarse localization of objects in the unseen video. We further adapt these retrieved object locations to the new video using an efficient warping scheme. The proposed method is validated on in-the-wild video surveillance datasets where we outperform state-of-the-art appearance-based trackers. We also introduce a new challenging dataset with complex object appearance changes.Comment: Under review with the IEEE Transactions on Circuits and Systems for Video Technolog

    Ultrafast switching time and third order nonlinear coefficients of microwave treated single walled carbon nanotube suspensions

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    Microwave treated water soluble and amide functionalized single walled carbon nanotubes have been investigated using femtosecond degenerate pump-probe and nonlinear transmission experiments. The time resolved differential transmission using 75 femtosecond pulse with the central wavelength of 790 nm shows a bi-exponential ultrafast photo-bleaching with time constants of of 160 fs (130 fs) and 920 fs (300 fs) for water soluble (amide functionalized) nanotubes. Open and closed aperture z-scans show saturation absorption and positive (negative) nonlinear refraction for water soluble (amide functionalized) nanotubes. Two photon absorption coefficient,beata ~250 cm/GW (650 cm/GW) and nonlinear index, gamma ~ 15 cm^2/pW (-30 cm^2/pW) are obtained from the theoretical fit in the saturation limit to the data for two types of nanotubes.Comment: 15 pages, 4 figure

    Characterization of Cold Sprayed CuCrAl-Coated and Uncoated GRCop-84 Substrates for Space Launch Vehicles

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    A newly developed Cu-23(wt.%)Cr-5%Al (CuCrAl) alloy is currently being considered as a protective coating for GRCop-84 (Cu-8(at.%)Cr-4%Nb). The coating was deposited on GRCop-84 substrates by the cold spray deposition technique. Cyclic oxidation tests conducted in air on both coated and uncoated substrates between 773 and 1073 K revealed that the coating remained intact and protected the substrate up to 1073 K. No significant weight loss of the coated specimens were observed at 773 and 873 K even after a cumulative cyclic time of 500 h. In contrast, the uncoated substrate lost as much as 80% of its original weight under similar test conditions. Low cycle fatigue tests revealed that the fatigue lives of thinly coated GRCop-84 specimens were similar to the uncoated specimens within the limits of experimental scatter. It is concluded that the cold sprayed CuCrAl coating is suitable for protecting GRCop-84 substrates

    GeoSoc: A Geo-cast-based Communication Protocol for Monitoring of Marine Environments

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    With the rapid development of society and the economy, an increasing number of human activities have gradually destroyed the marine environment. GeoSoc a node can take one of the following states: SINK: The master node of the whole network manager of receiving all the information that is collected by all the sensor nodes that make up the different clusters used for monitoring desired area. Cluster head: The node that coordinates a group of nodes that are part of a cluster and are responsible for the monitoring of an assigned area. Is responsible for establishing direct connection with the SINK node to transmit the information collected for all its sensor nodes. In case of losing SINK contact, can make use of a node. Gateway: A node that has connection with two Cluster head or a sensor node that does not reach its Cluster head. This type of nodes is used to increase network coverage and reduce loss connection by the nodes that make up the net.•Sensor Member: These nodes are responsible for Collect the information you want to monitor. Is the state that a node takes when it has already established Cluster head connection to a node? • Disconnected: A node has this been in two situations, 1) when it is activated for the first time and have to look for the cluster to which must be connected, 2) when it loses connection with its coordinator node and you have to perform the search for a new node coordinator

    MMB Cloud-Tree: Verifiable Cloud Service Selection

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    In the existing cloud brokerage system, the client does not have the ability to verify the result of the cloud service selection. There are possibilities that the cloud broker can be biased in selecting the best Cloud Service Provider (CSP) for a client. A compromised or dishonest cloud broker can unfairly select a CSP for its own advantage by cooperating with the selected CSP. To address this problem, we propose a mechanism to verify the CSP selection result of the cloud broker. In this verification mechanism, properties of every CSP will also be verified. It uses a trusted third party to gather clustering result from the cloud broker. This trusted third party is also used as a base station to collect CSP properties in a multi-agent\u27s system. Software Agents are installed and running on every CSP. The CSP is monitored by agents as the representative of the customer inside the cloud. These multi-agents give reports to a third party that must be trusted by CSPs, customers and the Cloud Broker. The third party provides transparency by publishing reports to the authorized parties (CSPs and Customers)

    Complex lithium ion dynamics in simulated LiPO3 glass studied by means of multi-time correlation functions

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    Molecular dynamics simulations are performed to study the lithium jumps in LiPO3 glass. In particular, we calculate higher-order correlation functions that probe the positions of single lithium ions at several times. Three-time correlation functions show that the non-exponential relaxation of the lithium ions results from both correlated back-and-forth jumps and the existence of dynamical heterogeneities, i.e., the presence of a broad distribution of jump rates. A quantitative analysis yields that the contribution of the dynamical heterogeneities to the non-exponential depopulation of the lithium sites increases upon cooling. Further, correlated back-and-forth jumps between neighboring sites are observed for the fast ions of the distribution, but not for the slow ions and, hence, the back-jump probability depends on the dynamical state. Four-time correlation functions indicate that an exchange between fast and slow ions takes place on the timescale of the jumps themselves, i.e., the dynamical heterogeneities are short-lived. Hence, sites featuring fast and slow lithium dynamics, respectively, are intimately mixed. In addition, a backward correlation beyond the first neighbor shell for highly mobile ions and the presence of long-range dynamical heterogeneities suggest that fast ion migration occurs along preferential pathways in the glassy matrix. In the melt, we find no evidence for correlated back-and-forth motions and dynamical heterogeneities on the length scale of the next-neighbor distance.Comment: 12 pages, 13 figure

    Eimeria species occurrence varies between geographic regions and poultry production systems and may influence parasite genetic diversity

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    Coccidiosis is one of the biggest challenges faced by the global poultry industry. Recent studies have highlighted the ubiquitous distribution of all Eimeria species which can cause this disease in chickens, but intriguingly revealed a regional divide in genetic diversity and population structure for at least one species, Eimeria tenella. The drivers associated with such distinct geographic variation are unclear, but may impact on the occurrence and extent of resistance to anticoccidial drugs and future subunit vaccines. India is one of the largest poultry producers in the world and includes a transition between E. tenella populations defined by high and low genetic diversity. The aim of this study was to identify risk factors associated with the prevalence of Eimeria species defined by high and low pathogenicity in northern and southern states of India, and seek to understand factors which vary between the regions as possible drivers for differential genetic variation. Faecal samples and data relating to farm characteristics and management were collected from 107 farms from northern India and 133 farms from southern India. Faecal samples were analysed using microscopy and PCR to identify Eimeria occurrence. Multiple correspondence analysis was applied to transform correlated putative risk factors into a smaller number of synthetic uncorrelated factors. Hierarchical cluster analysis was used to identify poultry farm typologies, revealing three distinct clusters in the studied regions. The association between clusters and presence of Eimeria species was assessed by logistic regression. The study found that large-scale broiler farms in the north were at greatest risk of harbouring any Eimeria species and a larger proportion of such farms were positive for E. necatrix, the most pathogenic species. Comparison revealed a more even distribution for E. tenella across production systems in south India, but with a lower overall occurrence. Such a polarised region- and system-specific distribution may contribute to the different levels of genetic diversity observed previously in India and may influence parasite population structure across much of Asia and Africa. The findings of the study can be used to prioritise target farms to launch and optimise appropriate anticoccidial strategies for long-term control
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