2,044 research outputs found
Optical Flow Requires Multiple Strategies (but only one network)
We show that the matching problem that underlies optical flow requires
multiple strategies, depending on the amount of image motion and other factors.
We then study the implications of this observation on training a deep neural
network for representing image patches in the context of descriptor based
optical flow. We propose a metric learning method, which selects suitable
negative samples based on the nature of the true match. This type of training
produces a network that displays multiple strategies depending on the input and
leads to state of the art results on the KITTI 2012 and KITTI 2015 optical flow
benchmarks
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Coupling a single electron on superfluid helium to a superconducting resonator.
Electrons on helium form a unique two-dimensional system on the interface of liquid helium and vacuum. A small number of trapped electrons on helium exhibits strong interactions in the absence of disorder, and can be used as a qubit. Trapped electrons typically have orbital frequencies in the microwave regime and can therefore be integrated with circuit quantum electrodynamics (cQED), which studies light-matter interactions using microwave photons. Here, we experimentally realize a cQED platform with the orbitals of single electrons on helium. We deterministically trap one to four electrons in a dot integrated with a microwave resonator, allowing us to study the electrons' response to microwaves. Furthermore, we find a single-electron-photon coupling strength of [Formula: see text] MHz, greatly exceeding the resonator linewidth [Formula: see text] MHz. These results pave the way towards microwave studies of Wigner molecules and coherent control of the orbital and spin state of a single electron on helium
NASA Perspective on Requirements for Development of Advanced Methods Predicting Unsteady Aerodynamics and Aeroelasticity
Over the past three years, the National Aeronautics and Space Administration (NASA) has initiated design, development, and testing of a new human-rated space exploration system under the Constellation Program. Initial designs within the Constellation Program are scheduled to replace the present Space Shuttle, which is slated for retirement within the next three years. The development of vehicles for the Constellation system has encountered several unsteady aerodynamics challenges that have bearing on more traditional unsteady aerodynamic and aeroelastic analysis. This paper focuses on the synergy between the present NASA challenges and the ongoing challenges that have historically been the subject of research and method development. There are specific similarities in the flows required to be analyzed for the space exploration problems and those required for some of the more nonlinear unsteady aerodynamic and aeroelastic problems encountered on aircraft. The aggressive schedule, significant technical challenge, and high-priority status of the exploration system development is forcing engineers to implement existing tools and techniques in a design and application environment that is significantly stretching the capability of their methods. While these methods afford the users with the ability to rapidly turn around designs and analyses, their aggressive implementation comes at a price. The relative immaturity of the techniques for specific flow problems and the inexperience with their broad application to them, particularly on manned spacecraft flight system, has resulted in the implementation of an extensive wind tunnel and flight test program to reduce uncertainty and improve the experience base in the application of these methods. This provides a unique opportunity for unsteady aerodynamics and aeroelastic method developers to test and evaluate new analysis techniques on problems with high potential for acquisition of test and even flight data against which they can be evaluated. However, researchers may be required to alter the geometries typically used in their analyses, the types of flows analyzed, and even the techniques by which computational tools are verified and validated. This paper discusses these issues and provides some perspective on the potential for new and innovative approaches to the development of methods to attack problems in nonlinear unsteady aerodynamics
The Expanding Role of Applications in the Development and Validation of CFD at NASA
This paper focuses on the recent escalation in application of CFD to manned and unmanned flight projects at NASA and the need to often apply these methods to problems for which little or no previous validation data directly applies. The paper discusses the evolution of NASA.s CFD development from a strict Develop, Validate, Apply strategy to sometimes allowing for a Develop, Apply, Validate approach. The risks of this approach and some of its unforeseen benefits are discussed and tied to specific operational examples. There are distinct advantages for the CFD developer that is able to operate in this paradigm, and recommendations are provided for those inclined and willing to work in this environment
Fabrication and characterization of superconducting circuit QED devices for quantum computation
We present fabrication and characterization procedures of devices for circuit
quantum electrodynamics (cQED). We have made 3 GHz cavities with quality
factors in the range 10^4--10^6, which allow access to the strong coupling
regime of cQED. The cavities are transmission line resonators made by
photolithography. They are coupled to the input and output ports via gap
capacitors. An Al-based Cooper pair box is made by ebeam lithography and Dolan
bridge double-angle evaporation in superconducting resonators with high quality
factor. An important issue is to characterize the quality factor of the
resonators. We present an RF-characterization of superconducting resonators as
a function of temperature and magnetic field. We have realized different
versions of the system with different box-cavity couplings by using different
dielectrics and by changing the box geometry. Moreover, the cQED approach can
be used as a diagnostic tool of qubit internal losses.Comment: 4 pages, 6 figures, Applied Superconductivity Conference 200
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