44,500 research outputs found
Design Patterns for Fusion-Based Object Retrieval
We address the task of ranking objects (such as people, blogs, or verticals)
that, unlike documents, do not have direct term-based representations. To be
able to match them against keyword queries, evidence needs to be amassed from
documents that are associated with the given object. We present two design
patterns, i.e., general reusable retrieval strategies, which are able to
encompass most existing approaches from the past. One strategy combines
evidence on the term level (early fusion), while the other does it on the
document level (late fusion). We demonstrate the generality of these patterns
by applying them to three different object retrieval tasks: expert finding,
blog distillation, and vertical ranking.Comment: Proceedings of the 39th European conference on Advances in
Information Retrieval (ECIR '17), 201
Improvement of the method of rats parabiosis with aortic anastomoses
This paper describes various aortic parabiotic procedures and discusses various problems concerning these procedures. The most satisfactory results, nearly 100 % of survival rate, can be achieved using longer sections of aortae of 2 to 5.month old rats. In these rats blood circulation between the parabionts has completely been established.</p
Microcrystalline silicon growth for heterojunction solar cells
Microcrystalline Si (m-Si) films with a 1.7eV energy bandgap and crystal size of several hundred A were e-beam evaporated on single crystalline Si (c-Si) to form a heterojunction with the substrate, or a window layer to a single crystalline p-n junction (heteroface structure). The goal was to enhance Voc by such uses of the larger bandgap m-Si, with the intriguing prospect of forming heterostructures with exact lattice match on each layer. The heterojunction structure was affected by interface and shunting problems and the best Voc achieved was only 482mV, well below that of single crystal Si homojunctions. The heteroface structure showed promise for some of the samples with p m-Si/p-n structure (the complementary structure did not show any improvement). Although several runs with different deposition conditions were run, the results were inconsistent. Any Voc enhancement obtained was too small to compensate for the current loss due to the extra absorption and poor carrier transport properties of the m-Si film
Averaged null energy condition in Loop Quantum Cosmology
Wormhole and time machine are very interesting objects in general relativity.
However, they need exotic matters which are impossible in classical level to
support them. But if we introduce the quantum effects of gravity into the
stress-energy tensor, these peculiar objects can be constructed
self-consistently. Fortunately, loop quantum cosmology (LQC) has the potential
to serve as a bridge connecting the classical theory and quantum gravity.
Therefore it provides a simple way for the study of quantum effect in the
semiclassical case. As is well known, loop quantum cosmology is very successful
to deal with the behavior of early universe. In the early stage, if taken the
quantum effect into consideration, inflation is natural because of the
violation of every kind of local energy conditions. Similar to the inflationary
universe, the violation of the averaged null energy condition is the necessary
condition for the traversable wormholes. In this paper, we investigate the
averaged null energy condition in LQC in the framework of effective
Hamiltonian, and find out that LQC do violate the averaged null energy
condition in the massless scalar field coupled model.Comment: 5 page
Approximation methods for control of acoustic/structure models with piezoceramic actuators
The active control of acoustic pressure in a 2-D cavity with a flexible boundary (a beam) is considered. Specifically, this control is implemented via piezoceramic patches on the beam which produces pure bending moments. The incorporation of the feedback control in this manner leads to a system with an unbounded input term. Approximation methods in this manner leads to a system with an unbounded input term. Approximation methods in the context of linear quadratic regulator (LQR) state space control formulation are discussed and numerical results demonstrating the effectiveness of this approach in computing feedback controls for noise reduction are presented
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