5,900 research outputs found
Industrial Parks in Russia: Conceptual Development of Projects
The paper presents a theoretical framework of industrial parks effectiveness as an element of economic policy to accelerate economy development in regions or municipalities. The article studies how historically such instruments were used in modern Russia. The paper states the necessity of extensive development of the industrial park concept and how it affects the chances of project realization and potential economic effectiveness. The main parts and blocks that should be taken into account during concept preparations are highlighted, and proposals for their content are made
An Innovative Approach to Achieve Compositionality Efficiently using Multi-Version Object Based Transactional Systems
In the modern era of multicore processors, utilizing cores is a tedious job.
Synchronization and communication among processors involve high cost. Software
transaction memory systems (STMs) addresses this issues and provide better
concurrency in which programmer need not have to worry about consistency
issues. Another advantage of STMs is that they facilitate compositionality of
concurrent programs with great ease. Different concurrent operations that need
to be composed to form a single atomic unit is achieved by encapsulating them
in a single transaction. In this paper, we introduce a new STM system as
multi-version object based STM (MVOSTM) which is the combination of both of
these ideas for harnessing greater concurrency in STMs. As the name suggests
MVOSTM, works on a higher level and maintains multiple versions corresponding
to each key. We have developed MVOSTM with the unlimited number of versions
corresponding to each key. In addition to that, we have developed garbage
collection for MVOSTM (MVOSTM-GC) to delete unwanted versions corresponding to
the keys to reduce traversal overhead. MVOSTM provides greater concurrency
while reducing the number of aborts and it ensures compositionality by making
the transactions atomic. Here, we have used MVOSTM for the list and hash-table
data structure as list-MVOSTM and HT- MVOSTM. Experimental results of
list-MVOSTM outperform almost two to twenty fold speedup than existing
state-of-the-art list based STMs (Trans-list, Boosting-list, NOrec-list,
list-MVTO, and list-OSTM). HT-MVOSTM shows a significant performance gain of
almost two to nineteen times better than existing state-of-the-art hash-table
based STMs (ESTM, RWSTMs, HT-MVTO, and HT-OSTM). MVOSTM with list and
hash-table shows the least number of aborts among all the existing STM
algorithms. MVOSTM satisfies correctness-criteria as opacity.Comment: 35 pages, 23 figure
Dark matter-wave solitons in the dimensionality crossover
We consider the statics and dynamics of dark matter-wave solitons in the
dimensionality crossover regime from 3D to 1D. There, using the nonpolynomial
Schr\"{o}dinger mean-field model, we find that the anomalous mode of the
Bogoliubov spectrum has an eigenfrequency which coincides with the soliton
oscillation frequency obtained by the 3D Gross-Pitaevskii model. We show that
substantial deviations (of order of 10% or more) from the characteristic
frequency ( being the longitudinal trap
frequency) are possible even in the purely 1D regime.Comment: Phys. Rev. A, in pres
Controlling the transverse instability of dark solitons and nucleation of vortices by a potential barrier
We study possibilities to suppress the transverse modulational instability
(MI) of dark-soliton stripes in two-dimensional (2D) Bose-Einstein condensates
(BECs) and self-defocusing bulk optical waveguides by means of quasi-1D
structures. Adding an external repulsive barrier potential (which can be
induced in BEC by a laser sheet, or by an embedded plate in optics), we
demonstrate that it is possible to reduce the MI wavenumber band, and even
render the dark-soliton stripe completely stable. Using this method, we
demonstrate the control of the number of vortex pairs nucleated by each spatial
period of the modulational perturbation. By means of the perturbation theory,
we predict the number of the nucleated vortices per unit length. The analytical
results are corroborated by the numerical computation of eigenmodes of small
perturbations, as well as by direct simulations of the underlying
Gross-Pitaevskii/nonlinear Schr\"{o}dinger equation.Comment: 10 pages, 7 figures. To appear on Phys. Rev. A, 201
Acoustic waves: should they be propagated forward in time, or forward in space?
The evolution of acoustic waves can be evaluated in two ways: either as a
temporal, or a spatial propagation. Propagating in space provides the
considerable advantage of being able to handle dispersion and propagation
across interfaces with remarkable efficiency; but propagating in time is more
physical and gives correctly behaved reflections and scattering without effort.
Which should be chosen in a given situation, and what compromises might have to
be made? Here the natural behaviors of each choice of propagation are compared
and contrasted for an ordinary second order wave equation, the time-dependent
diffusion wave equation, an elastic rod wave equation, and the Stokes'/ van
Wijngaarden's equations, each case illuminating a characteristic feature of the
technique. Either choice of propagation axis enables a partitioning the wave
equation that gives rise to a directional factorization based on a natural
"reference" dispersion relation. The resulting exact coupled bidirectional
equations then reduce to a single unidirectional first-order wave equation
using a simple "slow evolution" assumption that minimizes effect of subsequent
approximations, while allowing a direct term-to-term comparison between exact
and approximate theories.Comment: 12 pages, v2 correcte
Hyperbolic chaos in self-oscillating systems based on mechanical triple linkage: Testing absence of tangencies of stable and unstable manifolds for phase trajectories
Dynamical equations are formulated and a numerical study is provided for
self-oscillatory model systems based on the triple linkage hinge mechanism of
Thurston -- Weeks -- Hunt -- MacKay. We consider systems with holonomic
mechanical constraint of three rotators as well as systems, where three
rotators interact by potential forces. We present and discuss some quantitative
characteristics of the chaotic regimes (Lyapunov exponents, power spectrum).
Chaotic dynamics of the models we consider are associated with hyperbolic
attractors, at least, at relatively small supercriticality of the
self-oscillating modes; that follows from numerical analysis of the
distribution for angles of intersection of stable and unstable manifolds of
phase trajectories on the attractors. In systems based on rotators with
interacting potential the hyperbolicity is violated starting from a certain
level of excitation.Comment: 30 pages, 18 figure
Learning to predict closed questions on stack overflow
The paper deals with the problem of predicting whether the user’s question will be closed by the moderator on Stack Overflow, a popular question answering service devoted to software programming. The task along with data and evaluation metrics was offered as an open machine learning competition on Kaggle platform. To solve this problem, we employed a wide range of classification features related to users, their interactions, and post content. Classification was carried out using several machine learning methods. According to the results of the experiment, the most important features are characteristics of the user and topical features of the question. The best results were obtained using Vowpal Wabbit – an implementation of online learning based on stochastic gradient descent. Our results are among the best ones in overall ranking, although they were obtained after the official competition was over
Smooth and Non-Smooth Dependence of Lyapunov Vectors upon the Angle Variable on a Torus in the Context of Torus-Doubling Transitions in the Quasiperiodically Forced Henon Map
A transition from a smooth torus to a chaotic attractor in quasiperiodically
forced dissipative systems may occur after a finite number of torus-doubling
bifurcations. In this paper we investigate the underlying bifurcational
mechanism which seems to be responsible for the termination of the
torus-doubling cascades on the routes to chaos in invertible maps under
external quasiperiodic forcing. We consider the structure of a vicinity of a
smooth attracting invariant curve (torus) in the quasiperiodically forced Henon
map and characterize it in terms of Lyapunov vectors, which determine
directions of contraction for an element of phase space in a vicinity of the
torus. When the dependence of the Lyapunov vectors upon the angle variable on
the torus is smooth, regular torus-doubling bifurcation takes place. On the
other hand, the onset of non-smooth dependence leads to a new phenomenon
terminating the torus-doubling bifurcation line in the parameter space with the
torus transforming directly into a strange nonchaotic attractor. We argue that
the new phenomenon plays a key role in mechanisms of transition to chaos in
quasiperiodically forced invertible dynamical systems.Comment: 24 pages, 9 figure
Rationale for the use of benchmarking in territorial development
The article reveals the research of the importance of such effective marketing tool as benchmarking increasing the competitiveness of economic systems.
An algorithm is being developed for applying benchmarking technology to the specifics of the development and implementation of the strategy and tactics of regional development.
It is determined that the implementation of benchmarking technology in the territorial development in the context of modern Russian reality is prioritized in choosing a set of competitive advantages that the latter can have in the long term.peer-reviewe
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