363 research outputs found
Hopf cyclic cohomology in braided monoidal categories
We extend the formalism of Hopf cyclic cohomology to the context of braided
categories. For a Hopf algebra in a braided monoidal abelian category we
introduce the notion of stable anti-Yetter-Drinfeld module. We associate a
para-cocyclic and a cocyclic object to a braided Hopf algebra endowed with a
braided modular pair in involution in the sense of Connes and Moscovici. When
the braiding is symmetric the full formalism of Hopf cyclic cohomology with
coefficients can be extended to our categorical setting.Comment: 50 pages. One reference added. Proofs are visualized through braiding
diagrams. Final version to appear in `Homology, Homotopy and Applications
Employing Antenna Selection to Improve Energy-Efficiency in Massive MIMO Systems
Massive MIMO systems promise high data rates by employing large number of
antennas, which also increases the power usage of the system as a consequence.
This creates an optimization problem which specifies how many antennas the
system should employ in order to operate with maximal energy efficiency. Our
main goal is to consider a base station with a fixed number of antennas, such
that the system can operate with a smaller subset of antennas according to the
number of active user terminals, which may vary over time. Thus, in this paper
we propose an antenna selection algorithm which selects the best antennas
according to the better channel conditions with respect to the users, aiming at
improving the overall energy efficiency. Then, due to the complexity of the
mathematical formulation, a tight approximation for the consumed power is
presented, using the Wishart theorem, and it is used to find a deterministic
formulation for the energy efficiency. Simulation results show that the
approximation is quite tight and that there is significant improvement in terms
of energy efficiency when antenna selection is employed.Comment: To appear in Transactions on Emerging Telecommunications
Technologies, 12 pages, 8 figures, 2 table
Automated segmentation and morphological characterization of placental histology images based on a single labeled image
In this study, a novel method of data augmentation has been presented for the
segmentation of placental histological images when the labeled data are scarce.
This method generates new realizations of the placenta intervillous morphology
while maintaining the general textures and orientations. As a result, a
diversified artificial dataset of images is generated that can be used for
training deep learning segmentation models. We have observed that on average
the presented method of data augmentation led to a 42% decrease in the binary
cross-entropy loss of the validation dataset compared to the common approach in
the literature. Additionally, the morphology of the intervillous space is
studied under the effect of the proposed image reconstruction technique, and
the diversity of the artificially generated population is quantified. Due to
the high resemblance of the generated images to the real ones, the applications
of the proposed method may not be limited to placental histological images, and
it is recommended that other types of tissues be investigated in future
studies
Investigation on the Behavior of Bridge Piers Considering Rocking Isolation Constructed on Non-plastic Silts and Sands Using 1g Shaking Table Tests
Occurred damages on the bridge piers during earthquakes lead to significant financial losses worldwide every year and can cause social problems by disrupting traffic flow and transportation services. Rocking isolation of foundations is one of the damage reduction approaches to avoid structural damage on piers by transferring plastic hinges from piers to underlying soil media. The behavior of rocking foundations on non-plastic silts has not been investigated well until now in the literature. In this research, the characteristic seismic behavior of a bridge pier considering rocking isolation is evaluated using small-scale physical modeling tests. To this aim, eight shaking table tests (with sinusoidal excitations) are conducted where both sandy and silty materials are employed as the soil media. In addition to the effects of the underlying soil, the effects of the critical contact area ratio of the foundation and frequency of input motions are evaluated. Achieved results indicate that the considered bridge pier shows the same behavior trend for underlying silty soil and sandy one. However, because of the frequency-dependent behavior of non-plastic silty soil, the pier attracts lower accelerations and higher moments. Therefore, the achieved results show that the proposed design approaches of rocking foundations that are mostly extracted based on experimental studies on sands (or rarely on clay) can lead to non-conservative designs in silty soils
The Effect of Long Service Life on the Accuracy of Dentaport ZX Electronic Apex Locator
Introduction: Electronic apex locators are among the most acceptable instruments for determining root canal length. The present study aimed to evaluate the effect of long service life on the accuracy of the Dentaport Root ZX (DP ZX) electronic apex locator (EAL). Materials and Methods: In this study, fifty single-rooted freshly extracted human teeth were used. After determining the root canal length with a K-file and a dental operative microscope, the canals were measured with four separate DP ZX apex locators (two with more than 6 years of life service while two others had less than 6 years of life service). Data were analyzed by repeated ANOVA measurement. Results: No significant difference was found between the EALs with different years of life services (P=0.62). All EALs could determine root canal length with high accuracy of more than 94%. Conclusion: Based on the results of this in vitro study, the long service life had no significant impact on the accuracy of DP ZX EALs in terms of root canal length determination
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