13,696 research outputs found
Bounds for eigenvalue ratios of the Laplacian
For a bounded domain with a piecewise smooth boundary in an
-dimensional Euclidean space , we study eigenvalues of the
Dirichlet eigenvalue problem of the Laplacian. First we give a general
inequality for eigenvalues of the Laplacian. As an application, we study lower
order eigenvalues of the Laplacian and derive the ratios of lower order
eigenvalues of the Laplacian.Comment: 14 page
Rotor-to-stator rub vibration in centrifugal compressor
One example of excessive vibration encountered during loading of a centrifugal compressor train (H type compressor with HP casing) is discussed. An investigation was made of the effects of the dynamic load on the bearing stiffness and the rotor-bearing system critical speed. The high vibration occurred at a "threshold load," but the machine didn't run smoothly due to rubs even when it had passed through the threshold load. The acquisition and discussion of the data taken in the field as well as a description of the case history which utilizes background information to identify the malfunction conditions is presented. The analysis shows that the failures, including full reverse precession rub and exact one half subharmonic vibration, were caused by the oversize bearings and displacement of the rotor center due to foundation deformation and misalignment between gear shafts, etc. The corrective actions taken to alleviate excessive vibration and the problems which remain to be solved are also presented
EKONOMI SYARIAH Kajian Pembiayaan Murabahah Antara Teori Dan Praktek
Pembiayaan murabahah telah mendominasi dalam penyaluran dana pada bank syari'ah, jumlahnya hampir mencapai tujuh puluh lima persen dari total pembiayaan, hal ini memunculkan kesan semua transaksi penyaluran dana bank syari'ah sengaja di murabahah-kan, kemungkinan untuk meminimalisir resiko yang akan menimpa bank dalam setiap penyaluran dananya. Dibandingkan dengan mekanisme-mekanisme pembiyaan yang lain, murabahah adalah yang paling menguntungkan dan paling sedikit resikonya terhadap bank syari'ah. Tulisan ini bertujuan untuk mereview dan mengkaji praktik pembiayaan murabahah dari konsep teori dan praktik
Chiral geometry of higher excited bands in triaxial nuclei with particle-hole configuration
The lowest six rotational bands have been studied in the particle-rotor model
with the particle-hole configuration
and different triaxiality parameter . Both constant and spin-dependent
variable moments of inertial (CMI and VMI) are introduced. The energy spectra,
electromagnetic transition probabilities, angular momentum components and
-distribution have been examined. It is shown that, besides the band 1 and
band 2, the predicted band 3 and band 4 in the calculations of both CMI and VMI
for atomic nuclei with could be interpreted as chiral doublet
bands.Comment: 4 pages, 4 figure
Temporal sparse feature auto-combination deep network for video action recognition
In order to deal with action recognition for large‐scale video data, we present a spatio‐temporal auto‐combination deep network, which is able to extract deep features from short video segments by making full use of temporal contextual correlation of corresponding pixels among successive video frames. Based on conventional sparse encoding, we further consider the representative features in adjacent nodes of the hidden layers according to activation states similarities. A sparse auto‐combination strategy is applied to multiple input maps in each convolution stage. An information constraint of the representative features of hidden layer nodes is imposed to handle the adaptive sparse encoding of the topology. As a result, the learned features can represent the spatio‐temporal transition relationships better and the number of hidden nodes can be restricted to a certain range.
We conduct a series of experiments on two public data sets. The experimental results show that our approach is more effective and robust in video action recognition compared with traditional methods
Payments per claim model of outstanding claims reserve based on fuzzy linear regression
There are uncertainties in factors such as inflation. Historical data and variable values are ambiguous. They lead to ambiguity in the assessment of outstanding claims reserves. The payments per claim model can only perform point estimation. But the fuzzy linear regression is based on fuzzy theory and can directly deal with uncertainty in data. Therefore, this paper proposes a payments per claim model based on fuzzy linear regression. The linear regression method and fuzzy least square method are used to estimate the parameters of the fuzzy regression equation. And the estimated results are introduced into the payments per claim model. Then, the predicted value of each accident reserve is obtained. This result is compared with that of the traditional payments per claim model. And we find that the payments per claim model of estimating the fuzzy linear regression parameters based on the linear programming method is more effective. The model gives the width of the compensation amount for each accident year. In addition, this model solves the problem that the traditional payments per claim model cannot measure the dynamic changes in reserves
Polaronic transport induced by competing interfacial magnetic order in a LaCaMnO/BiFeO heterostructure
Using ultrafast optical spectroscopy, we show that polaronic behavior
associated with interfacial antiferromagnetic order is likely the origin of
tunable magnetotransport upon switching the ferroelectric polarity in a
LaCaMnO/BiFeO (LCMO/BFO) heterostructure. This is
revealed through the difference in dynamic spectral weight transfer between
LCMO and LCMO/BFO at low temperatures, which indicates that transport in
LCMO/BFO is polaronic in nature. This polaronic feature in LCMO/BFO decreases
in relatively high magnetic fields due to the increased spin alignment, while
no discernible change is found in the LCMO film at low temperatures. These
results thus shed new light on the intrinsic mechanisms governing
magnetoelectric coupling in this heterostructure, potentially offering a new
route to enhancing multiferroic functionality
Candidate MKiD nucleus 106Rh in triaxial relativistic mean-field approach with time-odd fields
The configuration-fixed constrained triaxial relativistic mean-field approach
is extended by including time-odd fields and applied to study the candidate
multiple chiral doublets (MKiD) nucleus 106Rh. The energy contribution from
time-odd fields and microscopical evaluation of center-of-mass correction as
well as the modification of triaxial deformation parameters beta, gamma due to
the time-odd fields are investigated. The contributions of the time-odd fields
to the total energy are 0.1-0.3 MeV and they modify slightly the gamma values.
However, the previously predicted multiple chiral doublets still exist.Comment: 9 pages, 3 figures, accepted for publication as a Brief Report in
Physical Review
Fuzzy interacting multiple model H∞ particle filter algorithm based on current statistical model
In this paper, fuzzy theory and interacting multiple model are introduced into H∞ filter-based particle filter to propose a new fuzzy interacting multiple model H∞ particle filter based on current statistical model. Each model uses H∞ particle filter algorithm for filtering, in which the current statistical model can describe the maneuver of target accurately and H∞ filter can deal with the nonlinear system effectively. Aiming at the problem of large amount of probability calculation in interacting multiple model by using combination calculation method, our approach calculates each model matching probability through the fuzzy theory, which can not only reduce the calculation amount, but also improve the state estimation accuracy to some extent. The simulation results show that the proposed algorithm can be more accurate and robust to track maneuvering target
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