15 research outputs found

    Saliency-weighted graphs for efficient visual content description and their applications in real-time image retrieval systems

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    YesThe exponential growth in the volume of digital image databases is making it increasingly difficult to retrieve relevant information from them. Efficient retrieval systems require distinctive features extracted from visually rich contents, represented semantically in a human perception-oriented manner. This paper presents an efficient framework to model image contents as an undirected attributed relational graph, exploiting color, texture, layout, and saliency information. The proposed method encodes salient features into this rich representative model without requiring any segmentation or clustering procedures, reducing the computational complexity. In addition, an efficient graph-matching procedure implemented on specialized hardware makes it more suitable for real-time retrieval applications. The proposed framework has been tested on three publicly available datasets, and the results prove its superiority in terms of both effectiveness and efficiency in comparison with other state-of-the-art schemes.Supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2013R1A1A2012904)

    SEABED INFRASTRUCTURE DEFENSE ANALYSIS

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    Traditional fleet operations and technologies are not adequately suited to counter the growing threat to undersea infrastructure from autonomous undersea systems. A cost-effective unmanned and manned system of systems is required to provide defense of this seabed infrastructure. This paper proposes possible system architectures to defend against this emerging threat to include passive barriers and active defense systems. The effectiveness of those candidate systems is evaluated through multiple agent-based modeling simulations of UUV versus UUV engagements. Analysis resulted in two major findings. First, point defense of critical assets is more effective than barrier defense. Second, system design must focus on minimizing the time required to effectively engage and neutralize threats, either through improvement to defensive UUV speed or investment in more UUV docking stations and sensor arrays. Cost analysis suggests that acquisition and operations cost of the recommended defensive system is less than the projected financial impact of a successful attack.http://archive.org/details/seabedinfrastruc1094562767Lieutenant, United States NavyLieutenant, United States NavyLieutenant, United States NavyMajor, Israel Defence ForcesMajor, Republic of Singapore Air ForceMajor, Republic of Singapore Air ForceCaptain, Singapore ArmyLieutenant, United States NavyLieutenant, United States NavyLieutenant, United States NavyMajor, Republic of Singapore Air ForceCaptain, Singapore ArmyCivilian, Ministry of Defense, SingaporeLieutenant, United States NavyLieutenant Commander, United States NavyLieutenant Junior Grade, United States NavyCivilian, Ministry of Defense, SingaporeCivilian, Ministry of Defense, SingaporeMajor, Republic of Singapore Air ForceMajor, United States Marine CorpsMajor, Singapore ArmyApproved for public release; distribution is unlimited

    Au@Hg<sub>x</sub>Cd<sub>1-x</sub>Te core@shell nanorods by sequential aqueous cation exchange for near-infrared photodetectors

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    We have explored the synthesis of Au@HgxCd1-xTe core@shell nanorods by sequential aqueous cation exchange (ACE) for near-infrared photodetector application. A number of related Au@telluride core/shell nanorod structures were put forwarded, taking advantage of multi-step transformations through a binary and then a ternary phase for the telluride shells. The latter have a high degree of crystallinity thanks to the step-wise ACE method. The use of only trace amounts of Cd2+ coordinated with tri-n-butylphosphine, assisted the phase transformation from an amorphous Ag2Te shell to a highly crystalline Ag3AuTe2 shell in the first stage; this was followed by a further cation exchange (CE) step with far higher Cd2+ levels to fabricate a highly crystalline CdTe shell, and with an additional CE with Hg2+ to convert it to a HgxCd1-xTe shell. The composition of the shell components and the well-controlled thickness of the shells enabled tunable surface plasmon resonance properties of the Au@telluride nanorods in the NIR region. Utilizing the enhanced NIR absorption, a hybrid photodetector structure of Au@HgxCd1-xTe nanorods on graphene was fabricated, showing visible to NIR (vis-NIR) broadband detection with high photoresponsivity (~106 A/W)
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