11,778 research outputs found
Pushing towards the Limit of Sampling Rate: Adaptive Chasing Sampling
Measurement samples are often taken in various monitoring applications. To
reduce the sensing cost, it is desirable to achieve better sensing quality
while using fewer samples. Compressive Sensing (CS) technique finds its role
when the signal to be sampled meets certain sparsity requirements. In this
paper we investigate the possibility and basic techniques that could further
reduce the number of samples involved in conventional CS theory by exploiting
learning-based non-uniform adaptive sampling.
Based on a typical signal sensing application, we illustrate and evaluate the
performance of two of our algorithms, Individual Chasing and Centroid Chasing,
for signals of different distribution features. Our proposed learning-based
adaptive sampling schemes complement existing efforts in CS fields and do not
depend on any specific signal reconstruction technique. Compared to
conventional sparse sampling methods, the simulation results demonstrate that
our algorithms allow less number of samples for accurate signal
reconstruction and achieve up to smaller signal reconstruction error
under the same noise condition.Comment: 9 pages, IEEE MASS 201
Resurvey of order and chaos in spinning compact binaries
This paper is mainly devoted to applying the invariant, fast, Lyapunov
indicator to clarify some doubt regarding the apparently conflicting results of
chaos in spinning compact binaries at the second-order post-Newtonian
approximation of general relativity from previous literatures. It is shown with
a number of examples that no single physical parameter or initial condition can
be described as responsible for causing chaos, but a complicated combination of
all parameters and initial conditions is responsible. In other words, a
universal rule for the dependence of chaos on each parameter or initial
condition cannot be found in general. Chaos does not depend only on the mass
ratio, and the maximal spins do not necessarily bring the strongest effect of
chaos. Additionally, chaos does not always become drastic when the initial spin
vectors are nearly perpendicular to the orbital plane, and the alignment of
spins cannot trigger chaos by itself.Comment: 16 pages, 7 figure
Kinetic Ballooning Mode Under Steep Gradient: High Order Eigenstates and Mode Structure Parity Transition
The existence of kinetic ballooning mode (KBM) high order (non-ground)
eigenstates for tokamak plasmas with steep gradient is demonstrated via
gyrokinetic electromagnetic eigenvalue solutions, which reveals that eigenmode
parity transition is an intrinsic property of electromagnetic plasmas. The
eigenstates with quantum number for ground state and for
non-ground states are found to coexist and the most unstable one can be the
high order states (). The conventional KBM is the state. It is
shown that the KBM has the same mode structure parity as the
micro-tearing mode (MTM). In contrast to the MTM, the KBM can be driven
by pressure gradient even without collisions and electron temperature gradient.
The relevance between various eigenstates of KBM under steep gradient and edge
plasma physics is discussed.Comment: 6 pages, 6 figure
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