1,130 research outputs found
Enriched Long-term Recurrent Convolutional Network for Facial Micro-Expression Recognition
Facial micro-expression (ME) recognition has posed a huge challenge to
researchers for its subtlety in motion and limited databases. Recently,
handcrafted techniques have achieved superior performance in micro-expression
recognition but at the cost of domain specificity and cumbersome parametric
tunings. In this paper, we propose an Enriched Long-term Recurrent
Convolutional Network (ELRCN) that first encodes each micro-expression frame
into a feature vector through CNN module(s), then predicts the micro-expression
by passing the feature vector through a Long Short-term Memory (LSTM) module.
The framework contains two different network variants: (1) Channel-wise
stacking of input data for spatial enrichment, (2) Feature-wise stacking of
features for temporal enrichment. We demonstrate that the proposed approach is
able to achieve reasonably good performance, without data augmentation. In
addition, we also present ablation studies conducted on the framework and
visualizations of what CNN "sees" when predicting the micro-expression classes.Comment: Published in Micro-Expression Grand Challenge 2018, Workshop of 13th
IEEE Facial & Gesture 201
Scanning tunneling spectroscopy of a magnetic atom on graphene in the Kondo regime
The Kondo effect in the system consisting of a magnetic adatom on the
graphene is studied. By using the non-equilibrium Green function method with
the slave-boson mean field approximation, the local density of state (LDOS) and
the conductance are calculated. For a doped graphene, the Kondo phase is
present at all time. Surprisingly, two kinds of Kondo regimes are revealed. But
for the undoped graphene, the Kondo phase only exists if the adatom's energy
level is beyond a critical value. The conductance is similar to the LDOS, thus,
the Kondo peak in the LDOS can be observed with the scanning tunneling
spectroscopy. In addition, in the presence of a direct coupling between the STM
tip and the graphene, the conductance may be dramatically enhanced, depending
on the coupling site.Comment: 4 pages, 4 figures, accepted by EP
Automated Testing of WS-BPEL Service Compositions: A Scenario-Oriented Approach
Nowadays, Service Oriented Architecture (SOA) has become one mainstream paradigm for developing distributed applications. As the basic unit in SOA, Web services can be composed to construct complex applications. The quality of Web services and their compositions is critical to the success of SOA applications. Testing, as a major quality assurance technique, is confronted with new challenges in the context of service compositions. In this paper, we propose a scenario-oriented testing approach that can automatically generate test cases for service compositions. Our approach is particularly focused on the service compositions specified by Business Process Execution Language for Web Services (WS-BPEL), a widely recognized executable service composition language. In the approach, a WS-BPEL service composition is first abstracted into a graph model; test scenarios are then derived from the model; finally, test cases are generated according to different scenarios. We also developed a prototype tool implementing the proposed approach, and an empirical study was conducted to demonstrate the applicability and effectiveness of our approach. The experimental results show that the automatic scenario-oriented testing approach is effective in detecting many types of faults seeded in the service compositions
Sensitivity Analysis of Inductive Power Transfer Systems With Voltage-Fed Compensation Topologies
Implications of the formation of small polarons in Li2O2 for Li-air batteries
Lithium-air batteries (LABs) are an intriguing next-generation technology due to their high theoretical energy density of similar to 11 kWh/kg. However, LABs are hindered by both poor rate capability and significant polarization in cell voltage, primarily due to the formation of Li2O2 in the air cathode. Here, by employing hybrid density functional theory, we show that the formation of small polarons in Li2O2 limits electron transport. Consequently, the low electron mobility mu = 10(-10)-10(-9) cm(2)/Vs contributes to both the poor rate capability and the polarization that limit the LAB power and energy densities. The self-trapping of electrons in the small polarons arises from the molecular nature of the conduction band states of Li2O2 and the strong spin polarization of the O 2p state. Our understanding of the polaronic electron transport in Li2O2 suggests that designing alternative carrier conduction paths for the cathode reaction could significantly improve the performance of LABs at high current densities.open20
Electric fields and valence band offsets at strained [111] heterojunctions
[111] ordered common atom strained layer superlattices (in particular the
common anion GaSb/InSb system and the common cation InAs/InSb system) are
investigated using the ab initio full potential linearized augmented plane wave
(FLAPW) method. We have focused our attention on the potential line-up at the
two sides of the homopolar isovalent heterojunctions considered, and in
particular on its dependence on the strain conditions and on the strain induced
electric fields. We propose a procedure to locate the interface plane where the
band alignment could be evaluated; furthermore, we suggest that the
polarization charges, due to piezoelectric effects, are approximately confined
to a narrow region close to the interface and do not affect the potential
discontinuity. We find that the interface contribution to the valence band
offset is substantially unaffected by strain conditions, whereas the total band
line-up is highly tunable, as a function of the strain conditions. Finally, we
compare our results with those obtained for [001] heterojunctions.Comment: 18 pages, Latex-file, to appear in Phys.Rev.
Alloy Stabilized Wurtzite Ground State Structures of Zinc-Blende Semiconducting Compounds
The ground state structures of the ABC wurtzite (WZ) alloys with
0.25, 0.5, and 0.75 are revealed by a ground state search using the
valence-force field model and density-functional theory total energy
calculations. It is shown that the ground state WZ alloy always has a lower
strain energy and formation enthalpy than the corresponding zinc-blende (ZB)
alloy. Therefore, we propose that the WZ phase can be stabilized through
alloying. This novel idea is supported by the fact that the WZ
AlPSb, AlPSb, ZnSTe, and
ZnSTe alloys in the lowest energy structures are more stable
than the corresponding ZB alloys. To our best knowledge, this is the first
example where the alloy adopts a structure distinct from both parent phases
Green Nanochemistry:Metal Oxide Nanoparticles and Porous Thin Films from Bare Metal Powders
Cataloged from PDF version of article.A universal, simple, robust, widely applicable and cost-effective aqueous process is described for a controlled oxidative dissolution process of micrometer-sized metal powders to form high-purity aqueous dispersions of colloidally stable 3-8 nm metal oxide nanoparticles. Their utilization for making single and multilayer optically transparent high-surface-area nanoporous films is demonstrated. This facile synthesis is anticipated to find numerous applications in materials science, engineering, and nanomedicine. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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