16,917 research outputs found
Perturbative analysis of generally nonlocal spatial optical solitons
In analogy to a perturbed harmonic oscillator, we calculate the fundamental
and some other higher order soliton solutions of the nonlocal nonlinear
Schroedinger equation (NNLSE) in the second approximation in the generally
nonlocal case. Comparing with numerical simulations we show that soliton
solutions in the 2nd approximation can describe the generally nonlocal soliton
states of the NNLSE more exactly than that in the zeroth approximation. We show
that for the nonlocal case of an exponential-decay type nonlocal response the
Gaussian-function-like soliton solutions can't describe the nonlocal soliton
states exactly even in the strongly nonlocal case. The properties of such
nonlocal solitons are investigated. In the strongly nonlocal limit, the
soliton's power and phase constant are both in inverse proportion to the 4th
power of its beam width for the nonlocal case of a Gaussian function type
nonlocal response, and are both in inverse proportion to the 3th power of its
beam width for the nonlocal case of an exponential-decay type nonlocal
response.Comment: 13 pages, 16 figures, accepted by Phys. Rev.
A Survey on Multisensor Fusion and Consensus Filtering for Sensor Networks
Multisensor fusion and consensus filtering are two fascinating subjects in the research of sensor networks. In this survey, we will cover both classic results and recent advances developed in these two topics. First, we recall some important results in the development ofmultisensor fusion technology. Particularly, we pay great attention to the fusion with unknown correlations, which ubiquitously exist in most of distributed filtering problems. Next, we give a systematic review on several widely used consensus filtering approaches. Furthermore, some latest progress on multisensor fusion and consensus filtering is also presented. Finally,
conclusions are drawn and several potential future research directions are outlined.the Royal Society of the UK, the National Natural Science Foundation of China under Grants 61329301, 61374039, 61304010, 11301118, and 61573246, the Hujiang Foundation of China under Grants C14002
and D15009, the Alexander von Humboldt Foundation of Germany, and the Innovation Fund Project for Graduate Student of Shanghai under Grant JWCXSL140
Fuzzy-logic-based control, filtering, and fault detection for networked systems: A Survey
This paper is concerned with the overview of the recent progress in fuzzy-logic-based filtering, control, and fault detection problems. First, the network technologies are introduced, the networked control systems are categorized from the aspects of fieldbuses and industrial Ethernets, the necessity of utilizing the fuzzy logic is justified, and the network-induced phenomena are discussed. Then, the fuzzy logic control strategies are reviewed in great detail. Special attention is given to the thorough examination on the latest results for fuzzy PID control, fuzzy adaptive control, and fuzzy tracking control problems. Furthermore, recent advances
on the fuzzy-logic-based filtering and fault detection problems are reviewed. Finally, conclusions are given and some possible future research directions are pointed out, for example, topics on two-dimensional networked systems, wireless networked control systems, Quality-of-Service (QoS) of networked systems, and fuzzy access control in open networked systems.This work was supported in part by the National Natural Science Foundation of China under Grants 61329301,
61374039, 61473163, and 61374127, the Hujiang Foundation of China under Grants C14002 andD15009, the Engineering and Physical Sciences Research Council (EPSRC) of the UK, the Royal Society of the UK, and the Alexander von Humboldt Foundation of Germany
Theoretical study of nuclear spin polarization and depolarization in self-assembled quantum dots
We investigate how the strain-induced nuclear quadrupole interaction
influences the degree of nuclear spin polarization in self-assembled quantum
dots. Our calculation shows that the achievable nuclear spin polarization in
In_{x}Ga_{1-x}As quantum dots is related to the concentration of indium and the
resulting strain distribution in the dots. The interplay between the nuclear
quadrupole interaction and Zeeman splitting leads to interesting features in
the magnetic field dependence of the nuclear spin polarization. Our results are
in qualitative agreement with measured nuclear spin polarization by various
experimental groups.Comment: 14 pages, 13 figures, submitted to Physical Review
Integrated photonic qubit quantum computing on a superconducting chip
We study a quantum computing system using microwave photons in transmission
line resonators on a superconducting chip as qubits. We show that all control
necessary for quantum computing can be implemented by coupling to Josephson
devices on the same chip, and take advantage of their strong inherent
nonlinearities to realize qubit interactions. We analyze the gate error rate to
demonstrate that our scheme is realistic even for Josephson devices with
limited decoherence times. A conceptually innovative solution based on existing
technologies, our scheme provides an integrated and scalable approach to the
next key milestone for photonic qubit quantum computing.Comment: 5 pages, 3 figure
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Coal mine low power laser methane detection and alarm instrument
At present, the portable carrier catalytic methane detection and alarm instrument for coal mine generally has many problems, such as high power consumption, short standby time, low detection accuracy, few parameters and single function, which can not meet the rapid development needs of mine safety. In this paper, a low power portable laser methane detection and alarm instrument based on tunable laser absorption spectroscopy (TDLAS) is designed. The instrument can detect methane concentration, ambient temperature and ambient pressure at the same time. It has the functions of sound and light alarm, historical data storage and query, and integrates Wi-Fi to realize data wireless transmission. The instrument can work continuously for 36 hours, and the response time is less than 15 seconds. It has the function of self-diagnosis. The overall performance of the instrument has been greatly improved compared with the traditional mine methane portable instrument. A mobile methane alarm Internet of things(IOT) system for coal mine based on portable instrument has been developed, which realizes real-time upload of data and cloud analysis, makes the traditional mine gas monitoring and control system powerfully supplemented, greatly improves the detection level of coal mine gas, and has broad application prospects
Effects of dynamical phases in Shor's factoring algorithm with operational delays
Ideal quantum algorithms usually assume that quantum computing is performed
continuously by a sequence of unitary transformations. However, there always
exist idle finite time intervals between consecutive operations in a realistic
quantum computing process. During these delays, coherent "errors" will
accumulate from the dynamical phases of the superposed wave functions. Here we
explore the sensitivity of Shor's quantum factoring algorithm to such errors.
Our results clearly show a severe sensitivity of Shor's factorization algorithm
to the presence of delay times between successive unitary transformations.
Specifically, in the presence of these {\it coherent "errors"}, the probability
of obtaining the correct answer decreases exponentially with the number of
qubits of the work register. A particularly simple phase-matching approach is
proposed in this paper to {\it avoid} or suppress these {\it coherent errors}
when using Shor's algorithm to factorize integers. The robustness of this
phase-matching condition is evaluated analytically or numerically for the
factorization of several integers: , and 33.Comment: 8 pages with 5 figure
What Makes a Better Annuity?
The wide gulf between actual and predicted annuity demand has been well documented. However, a comparable gap exists between the current and ideal annuity market. In a world with costly and limited annuity products, we investigate what types of new annuity products could improve annuity market participation and increase individual welfare. We find that participation gains are most likely for new annuity products that focus on late-life payouts which offer a large price discount relative to their financial market analogues. For example, the marginal utility from the first dollar allocated to a late-life annuity can be several times that of an immediate annuity. Our welfare analysis indicates that an individual’s current assets suggest desirable new annuity products since annuities that lower the cost of the existing consumption plan necessarily improve welfare. Finally, we consider the implications for annuity demand if new annuity products ultimately complete the annuity market. Given access to a complete market, we find all individuals only purchase annuity contracts with a significant time gap between purchase and payout. At a minimum, enough time must pass between purchase and payout to build up a mortality discount sufficient to overcome the cost of creating the contract. Since most existing annuity products, such as immediate annuities, do not have this feature, few current annuity contract configurations are likely to survive significant product innovation. Taken together, our results indicate that there is ample opportunity for innovation to spur annuity demand and improve individual welfare
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