Adaptive End-to-End Metric Learning for Zero-Shot Cross-Domain Slot Filling

Recently slot filling has witnessed great development thanks to deep learning and the availability of large-scale annotated data. However, it poses a critical challenge to handle a novel domain whose samples are never seen during training. The recognition performance might be greatly degraded due to severe domain shifts. Most prior works deal with this problem in a two-pass pipeline manner based on metric learning. In practice, these dominant pipeline models may be limited in computational efficiency and generalization capacity because of non-parallel inference and context-free discrete label embeddings. To this end, we re-examine the typical metric-based methods, and propose a new adaptive end-to-end metric learning scheme for the challenging zero-shot slot filling. Considering simplicity, efficiency and generalizability, we present a cascade-style joint learning framework coupled with context-aware soft label representations and slot-level contrastive representation learning to mitigate the data and label shift problems effectively. Extensive experiments on public benchmarks demonstrate the superiority of the proposed approach over a series of competitive baselines.Comment: Accepted to EMNLP 2023 (Main, Long Paper

Poisson-like effect for flexural waves in periodically perforated thin plates

[EN] The Poisson-like effect, describing the redirection of waves by 90 degrees, is shown to be feasible for flexural waves propagating in perforated thin plates. It is demonstrated that the lowest order symmetric leaky guided mode (S0 mode) is responsible for the splitting of wave motion in two orthogonal directions. The S0 mode shows a feature of stationary waves containing standing wave modes in one and two orthogonal directions for smaller and larger holes, respectively. The former case is well understood thanks to the phenomenon of Wood's anomaly, which was first observed in optical gratings supposed to be transparent. On the contrary, the strong scattering caused by the larger holes leads to a mixed mode occurring when the incident wave is totally transmitted. The mixed mode easily couples with the incoming waves and, therefore, the Poisson-like effect activated under this mechanism is much stronger. Using the Poisson-like effect, a device is proposed in which about 82% of the incident mechanical energy is redirected to the perpendicular direction. Results obtained with arrays of free holes also apply to inclusions with parameters properly chosen. The findings may provide applications in beam splitting and waveguiding. (C) 2018 Acoustical Society of America.Work supported by the Ministerio de Economia y Competitividad of Spain and the EU Fondo Europeo de Desarrollo Regional under Project No. TEC2014-53088-C3-1-R, and the National Natural Science Foundation of China under Grants Nos. 11432004 and 11421091. P.G. acknowledges a scholarship with No. 201606120070 provided by China Scholarship Council.Gao, P.; Sánchez-Dehesa Moreno-Cid, J.; Wu, L. (2018). Poisson-like effect for flexural waves in periodically perforated thin plates. The Journal of the Acoustical Society of America. 144(2):1053-1058. https://doi.org/10.1121/1.5051648S10531058144

Single-phase metamaterial plates for broadband vibration suppression at low frequencies

[EN] By studying platonic crystals based on lattices of cavities containing N-beam resonators, we conclude that crystals made of 1-beam resonators easily produce low-frequency omnidirectional bandgaps. Based on this favorable property, hardly obtained for resonant cavities containing a higher number of beams N >= 2, we have designed single-phase metamaterial plates for the suppression of low frequency flexural waves in a broad range of frequencies. These metamaterials are obtained by using resonant cavities containing a multiple number M of identical 1-beam resonators uniformly distributed in the cavity. Square lattices of this type of resonators have been studied by using the impedance matrix approach and the multiple scattering method. This semi-analytical method has been employed to show the existence of complete bandgaps whose width can be optimized by increasing M. For the case M = 4, the largest number of resonators studied here, three complete bandgaps separated by two narrow passbands appear in the band structure. The formation of these complete bandgaps originates from the dynamic interaction between different local resonators as well as their interaction with the propagating waves in the host plate. By using composite structures consisting of platonic crystal slabs with complementary bandgaps, these separated bandgaps easily merge into a broadband wave attenuation region. The normalized width, defined as the percentage of the bandwidth to its central frequency, reaches 95.3%, representing an enhancement of about one order of magnitude compared with the absolute bandwidth obtained for the case of a single 1-beam resonator in the cavity. It is shown that the gaps can be easily tuned to lower frequencies by changing the geometrical parameters, such as the length of the beam, the radius and thickness of the smaller circular plate. Since the metamaterial is made of a single-phase material without attaching heavy masses, the work reported here provides a simple approach to construct low-cost structures with potential applications in aeronautic and astronautic industries for broadband vibration suppression at low frequencies. (C) 2018 Published by Elsevier Ltd.This work was supported by the Ministerio de Economia y Competitividad of the Spanish government and the European Union Fondo Europeo de Desarrollo Regional (FEDER) [Grant No. TEC2014-53088-C3-1-R], and the National Natural Science Foundation of China [Grant Nos. 11432004 and 11421091]. Penglin Gao acknowledges a scholarship provided by China Scholarship Council [Grant No. 201606120070].Gao, P.; Climente Alarcón, A.; Sánchez-Dehesa Moreno-Cid, J.; Wu, L. (2019). Single-phase metamaterial plates for broadband vibration suppression at low frequencies. Journal of Sound and Vibration. 444:108-126. https://doi.org/10.1016/j.jsv.2018.12.022S10812644

Theoretical study of platonic crystals with periodically structured N-beam resonators

[EN] A multiple scattering theory is applied to study the properties of flexural waves propagating in a plate with periodically structured N-beam resonators. Each resonator consists of a circular hole containing an inner disk connected to background plate with N rectangular beams. The Bloch theorem is employed to obtain the band structure of a two-dimensional lattice containing a single resonator per unit cell. Also, a numerical algorithm has been developed to get the transmittance through resonator slabs infinitely long in the direction perpendicular to the incident wave. For the numerical validation, a square lattice of 2-beam resonators has been comprehensively analyzed. Its band structure exhibits several flat bands, indicating the existence of local resonances embedded in the structure. Particularly, the one featured as the fundamental mode of the inner disk opens a bandgap at low frequencies. This mode has been fully described in terms of a simple spring-mass model. As a practical application of the results obtained, a homogenization approach has been employed to design a focusing lens for flexural waves, where the index gradient is obtained by adjusting the orientation of the resonators beams. Numerical experiments performed within the framework of a three-dimensional finite element method have been employed to discuss the accuracy of the models described here. Published by AIP Publishing.This work was supported by the Ministerio de Economia y Competitividad of the Spanish government and the European Union Fondo Europeo de Desarrollo Regional (FEDER) through Project No. TEC2014-53088-C3-1-R, and the National Science Foundation of China under Grant No. 11432004. Penglin Gao acknowledges a scholarship with No. 201606120070 provided by China Scholarship Council.Gao, P.; Climente Alarcón, A.; Sánchez-Dehesa Moreno-Cid, J.; Wu, L. (2018). Theoretical study of platonic crystals with periodically structured N-beam resonators. Journal of Applied Physics. 123(9). https://doi.org/10.1063/1.5009170S123

TAMEP are brain tumor parenchymal cells controlling neoplastic angiogenesis and progression

Aggressive brain tumors like glioblastoma depend on support by their local environment and subsets of tumor parenchymal cells may promote specific phases of disease progression. We investigated the glioblastoma microenvironment with transgenic lineage-tracing models, intravital imaging, single-cell transcriptomics, immunofluorescence analysis as well as histopathology and characterized a previously unacknowledged population of tumor-associated cells with a myeloid-like expression profile (TAMEP) that transiently appeared during glioblastoma growth. TAMEP of mice and humans were identified with specific markers. Notably, TAMEP did not derive from microglia or peripheral monocytes but were generated by a fraction of CNS-resident, SOX2-positive progenitors. Abrogation of this progenitor cell population, by conditional Sox2-knockout, drastically reduced glioblastoma vascularization and size. Hence, TAMEP emerge as a tumor parenchymal component with a strong impact on glioblastoma progression