175,186 research outputs found
RMPD - A Recursive Mid-Point Displacement Algorithm for Path Planning
Motivated by what is required for real-time path planning, the paper starts
out by presenting sRMPD, a new recursive "local" planner founded on the key
notion that, unless made necessary by an obstacle, there must be no deviation
from the shortest path between any two points, which would normally be a
straight line path in the configuration space. Subsequently, we increase the
power of sRMPD by using it as a "connect" subroutine call in a higher-level
sampling-based algorithm mRMPD that is inspired by multi-RRT. As a consequence,
mRMPD spawns a larger number of space exploring trees in regions of the
configuration space that are characterized by a higher density of obstacles.
The overall effect is a hybrid tree growing strategy with a trade-off between
random exploration as made possible by multi-RRT based logic and immediate
exploitation of opportunities to connect two states as made possible by sRMPD.
The mRMPD planner can be biased with regard to this trade-off for solving
different kinds of planning problems efficiently. Based on the test cases we
have run, our experiments show that mRMPD can reduce planning time by up to 80%
compared to basic RRT
A wideband CPW ring power combiner with low insertion loss and high port isolation
In this paper we present a coplanar waveguide (CPW)-based ring power combiner that exhibits less than 0.8 dB insertion loss, better than 15 dB port match and higher than 22 dB isolation loss over the frequency range from 50 GHz to 100 GHz. Compared with the conventional 2-way Wilkinson combiner, the proposed ring power combiner replaces the resistor between the two input ports with two quasi quarter-wave CPWs, a 180º CPW phase inverter, and two resistors that lead to frequency-insensitive port isolation and wideband port match. The power combiner is realized using an electron beam-based GaAs MMIC process along with simple electron beam airbridge technology. These results agree well with 3D full-wave simulations
Photoproduction and Radiative Decay of Spin 1/2 and 3/2 Pentaquarks
We study photoproduction and radiative decays of pentauqarks paying
particular attention to the differences between spin-1/2 and spin-3/2, positive
and negative parities of pentaquarks. Detailed study of these processes can not
only give crucial information about the spin, but also the parity of
pentaquarks.Comment: 14 pages, 7 figure
Investigation of refractory dielectric for integrated circuits Second quarterly report, Dec. 1968
Process development for chemical deposition of aluminum oxide films as refractory dielectrics for integrated circuit
Effects of hadronic loops on the direct CP violation of
It is well known that the final state interaction plays an important role in
the decays of -meson. The contribution of the final state interaction which
is supposed to be long-distance effects, to the concerned processes can
interfere with that of the short-distance effects produced via the tree and/or
loop diagrams at quark-gluon level. The interference may provide a source for
the direct CP violation in the process . We find that a typical value of when the
final state interaction effect is taken into account can be about -22% which is
different from that without the final state interaction effect. Therefore, when
we extract information on CP violation from the data which will be available at
LHCb and the new experiments in -factories, the contribution from the final
state interaction must be included. This study may be crucial for searching new
physics in the future.Comment: 15 pages, 3 figures, 2 tables. More discussion adde
Investigation of refractory dielectric for integrated circuits Third quarterly report, Feb. 1969
Research and development on refractory dielectrics for integrated circuit
Charge order, metallic behavior and superconductivity in La_{2-x}Ba_xCuO_4 with x=1/8
The ab-plane optical properties of a cleaved single crystal of
La_{2-x}Ba_xCuO_4 for x=1/8 (T_c ~ 2.4 K) have been measured over a wide
frequency and temperature range. The low-frequency conductivity is Drude-like
and shows a metallic response with decreasing temperature. However, below ~ 60
K, corresponding to the onset of charge-stripe order, there is a rapid loss of
spectral weight below about 40 meV. The gapping of single-particle excitations
looks surprisingly similar to that observed in superconducting
La_{2-x}Sr_{x}CuO_4, including the presence of a residual Drude peak with
reduced weight; the main difference is that the lost spectral weight moves to
high, rather than zero, frequency, reflecting the absence of a bulk
superconducting condensate.Comment: 4 pages, with 1 table and 3 figure
SCOOTER: A compact and scalable dynamic labeling scheme for XML updates
Although dynamic labeling schemes for XML have been the
focus of recent research activity, there are significant challenges still to be overcome. In particular, though there are labeling schemes that ensure a compact label representation when creating an XML document, when the document is subject to repeated and arbitrary deletions and insertions, the labels grow rapidly and consequently have a significant impact on query and update performance. We review the outstanding issues todate and in this paper we propose SCOOTER - a new dynamic labeling scheme for XML. The new labeling scheme can completely avoid relabeling
existing labels. In particular, SCOOTER can handle frequently skewed insertions gracefully. Theoretical analysis and experimental results confirm the scalability, compact representation, efficient growth rate and performance of SCOOTER in comparison to existing dynamic labeling schemes
Mean parity of single quantum excitation of some optical fields in thermal environments
The mean parity (the Wigner function at the origin) of excited binomial
states, excited coherent states and excited thermal states in thermal channel
is investigated in details. It is found that the single-photon excited binomial
state and the single-photon excited coherent state exhibit certain similarity
in the aspect of their mean parity in the thermal channel. We show the negative
mean parity can be regarded as an indicator of nonclassicality of single-photon
excitation of optical fields with a little coherence, especially for the
single-photon excited thermal states.Comment: 4 pages, 4 figures, RevTex4; PACS numbers: 42.50.Dv, 03.65.Yz,
05.40.Ca; Three typo errors have been correcte
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