63 research outputs found
Revisit Few-shot Intent Classification with PLMs: Direct Fine-tuning vs. Continual Pre-training
We consider the task of few-shot intent detection, which involves training a
deep learning model to classify utterances based on their underlying intents
using only a small amount of labeled data. The current approach to address this
problem is through continual pre-training, i.e., fine-tuning pre-trained
language models (PLMs) on external resources (e.g., conversational corpora,
public intent detection datasets, or natural language understanding datasets)
before using them as utterance encoders for training an intent classifier. In
this paper, we show that continual pre-training may not be essential, since the
overfitting problem of PLMs on this task may not be as serious as expected.
Specifically, we find that directly fine-tuning PLMs on only a handful of
labeled examples already yields decent results compared to methods that employ
continual pre-training, and the performance gap diminishes rapidly as the
number of labeled data increases. To maximize the utilization of the limited
available data, we propose a context augmentation method and leverage
sequential self-distillation to boost performance. Comprehensive experiments on
real-world benchmarks show that given only two or more labeled samples per
class, direct fine-tuning outperforms many strong baselines that utilize
external data sources for continual pre-training. The code can be found at
https://github.com/hdzhang-code/DFTPlus.Comment: ACL 2023, Finding
Study of Peeling of Single Crystal Silicon by Intense Pulsed Ion Beam
The surface peeling process induced by intense
pulsed ion beam (IPIB) irradiation was studied.
Single crystal silicon specimens were treated by
IPIB with accelerating voltage of 350 kV current
density of 130 A/cm2. It is observed that
under smaller numbers of IPIB shots, the surface
may undergo obvious melting and evaporation..
Study of Peeling of Single Crystal Silicon by Intense Pulsed Ion Beam
The surface peeling process induced by intense
pulsed ion beam (IPIB) irradiation was studied.
Single crystal silicon specimens were treated by
IPIB with accelerating voltage of 350 kV current
density of 130 A/cm2. It is observed that
under smaller numbers of IPIB shots, the surface
may undergo obvious melting and evaporation..
Study on Ablation Products of Zinc by Intense Pulsed Ion Beam Irradiation
As a kind of flash heat source, intense pulse ion
beam can be used for material surface modification.
The ablation effect has important influence
on interaction between IPIB and material. Therefore,
the understanding of ablation mechanism is
of great significance to IPIB application..
Study of the intense pulsed electron beam energy spectrum from BIPPAB-450
Intense pulsed particle beams have been
widely used and studied as an effective method
for material surface modification in the past
several decades. Beihang Intense Pulsed PArticle
Beams 450 accelerator (BIPPAB-450) can
produce Intense Pulsed Ion Beams (IPIB) and
Electron Beams (IPEB) in two modes with different
Magnetically Insulated Diodes (MID).
For IPEB, the pulse duration, accelerating voltage,
total beam current are 100ns, up to 450keV
and 3kA, respectively..
Enhancing the outcoupling efficiency of quantum dot LEDs with internal nano-scattering pattern
We report an effective method to extract light from quantum-dot light emitting diodes (QLEDs) by embedding an internal nano-scattering pattern structure. We use finite-difference time-domain method to analyze the light extraction efficiency of red QLEDs with periodic, quasi-random, and random internal nano-scattering pattern structures. Our simulation results indicate that random internal nano-scattering pattern can greatly enhance the outcoupling efficiency while keeping wide viewing angle for the red QLED. Similar results are obtained by extending this approach to green and blue QLEDs. With the proposed red, green, and blue QLEDs combination, we achieve 105.1% Rec. 2020 color gamut in CIE 1976 color space. We demonstrate that internal nano-scattering pattern structures are attractive for display applications, especially for enhancing the outcoupling efficiency of blue QLEDs
Highly Efficient Air-Mode Silicon Metasurfaces for Visible Light Operation Embedded in a Protective Silica Layer
Dielectric metasurfaces have significant potential for delivering miniaturized optical systems with versatile functionalities, leading to applications in various fields such as orbital angular momentum generation, imaging, and holography. Among the different materials, crystalline silicon has the advantage of technological maturity and high refractive index, which increases design flexibility and processing latitude. The second, and often overlooked, advantage of silicon is that it affords embedding the metasurface in a protective material such as silica, which is essential for practical applications. The trade-off against this high refractive index is silicon's absorption at visible wavelength, which requires new design strategies. Here, such a strategy based on metasurfaces supporting air modes is identified that can lead to a transmission efficiency as high as 87% at a wavelength of 532 nm. This exceptional efficiency is obtained by using the high index to confine the electric field in the periphery of the meta-atoms, thereby reducing absorption losses. As an example, the design of a fully embedded metasurface is described that can generate vortex beams with various orders of orbital angular momentum. It is envisioned that the proposed strategy paves the way for practical applications of high-efficiency metasurfaces based on crystalline silicon
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