345 research outputs found
On the two-point boundary value problem for quadratic second-order differential equations and inclusions on manifolds
The two-point boundary value problem for second-order
differential inclusions of the form (D/dt)m˙(t)∈F(t,m(t),m˙(t)) on complete Riemannian manifolds is
investigated for a couple of points, nonconjugate along at least
one geodesic of Levi-Civitá connection, where D/dt is the covariant derivative of Levi-Civitá connection and F(t,m,X) is a set-valued vector with quadratic or less than quadratic growth in
the third argument. Some interrelations between certain geometric
characteristics, the distance between points, and the norm of
right-hand side are found that guarantee solvability of the above
problem for F with quadratic growth in X. It is shown that
this interrelation holds for all inclusions with F having less than quadratic growth in X, and so for them the problem is solvable
Analytical, Optimal, and Sparse Optimal Control of Traveling Wave Solutions to Reaction-Diffusion Systems
This work deals with the position control of selected patterns in
reaction-diffusion systems. Exemplarily, the Schl\"{o}gl and FitzHugh-Nagumo
model are discussed using three different approaches. First, an analytical
solution is proposed. Second, the standard optimal control procedure is
applied. The third approach extends standard optimal control to so-called
sparse optimal control that results in very localized control signals and
allows the analysis of second order optimality conditions.Comment: 22 pages, 3 figures, 2 table
Spring stratospheric circulation transition and mid-latitude sporadic E-layer
Using ionospheric data from a 32-year period for 8 mid-latitude stations within the European part of Russia, the dependence of intensity of an sporadic-E layer during the summer period on the start date of the spring seasonal transition of zonal circulation in the stratosphere was investigated. In those years with an early circulation transition, the sporadic-E layer intensity was increased by a factor of 1.5 compared with years with a late circulation transition. © 1997 COSPAR. Published by Elsevier Science Ltd
Effects of planetary waves in parameters of the midlatitude sporadic E layer
The spatial structure of the planetary waves in the frequency parameters of the sporadic E layer have been studied based on an analysis of the 30-year series of the ionospheric data for the midlatitude region of the Northern Hemisphere, which made it possible to observe the planetary waves with zonal wavenumbers 1, 2, and 3. The characteristic periods of existence have been revealed for these waves, and the seasonal distributions of these periods have been constructed. These waves can be considered among quasistationary formations according to their character; i.e., these waves are stationary or slowly move during long time intervals but can abruptly change the initial phase during 1-2 days. Two clearly defined zones between 30°-60° E and 210°-240° E have been detected as a result of an analysis of the longitudinal belts where an abrupt change in the initial phases of these waves is most frequent. © Pleiades Publishing, Ltd. 2009
The influence of lower atmosphere dynamics on the mid-latitude sporadic E-layer
The relationship between the occurrence of intense sporadic-E layers and features of tropospheric weather has been investigated. It has been found that, as certain features of the tropospheric pressure field (as identified from meteorological charts) develop over specific geographic regions, the probability of intense sporadic-E layers increases. Investigating the 500 mb chart has shown that the probability of occurrence of intense sporadic-E layers increases in response to distortion of patterns of zonal westerly flows. © 1997 COSPAR. Published by Elsevier Science Ltd
Domain-size control by global feedback in bistable systems
We study domain structures in bistable systems such as the Ginzburg-Landau
equation. The size of domains can be controlled by a global negative feedback.
The domain-size control is applied for a localized spiral pattern
The memristive artificial neuron high level architecture for biologically inspired robotic systems
© 2017 IEEE. In this paper we propose a new hardware architecture for the implementation of an artificial neuron based on organic memristive elements and operational amplifiers. This architecture is proposed as a possible solution for the integration and deployment of the cluster based bio- realistic simulation of a mammalian brain into a robotic system. Originally, this simulation has been developed through a neuro-biologically inspired cognitive architecture (NeuCogAr) re-implementing basic emotional states or affects in a computational system. This way, the dopamine, serotonin and noradrenaline pathways developed in NeuCogAr are synthesized through hardware memristors suitable for the implementation of basic emotional states or affects on a biologically inspired robotic system
Simultaneous Embeddability of Two Partitions
We study the simultaneous embeddability of a pair of partitions of the same
underlying set into disjoint blocks. Each element of the set is mapped to a
point in the plane and each block of either of the two partitions is mapped to
a region that contains exactly those points that belong to the elements in the
block and that is bounded by a simple closed curve. We establish three main
classes of simultaneous embeddability (weak, strong, and full embeddability)
that differ by increasingly strict well-formedness conditions on how different
block regions are allowed to intersect. We show that these simultaneous
embeddability classes are closely related to different planarity concepts of
hypergraphs. For each embeddability class we give a full characterization. We
show that (i) every pair of partitions has a weak simultaneous embedding, (ii)
it is NP-complete to decide the existence of a strong simultaneous embedding,
and (iii) the existence of a full simultaneous embedding can be tested in
linear time.Comment: 17 pages, 7 figures, extended version of a paper to appear at GD 201
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