38 research outputs found
Flatness-Aware Prompt Selection Improves Accuracy and Sample Efficiency
With growing capabilities of large language models, prompting them has become
the dominant way to access them. This has motivated the development of
strategies for automatically selecting effective language prompts. In this
paper, we introduce prompt flatness, a new metric to quantify the expected
utility of a language prompt. This metric is inspired by flatness
regularization in statistical learning that quantifies the robustness of the
model towards its parameter perturbations. We provide theoretical foundations
for this metric and its relationship with other prompt selection metrics,
providing a comprehensive understanding of existing methods. Empirically, we
show that combining prompt flatness with existing metrics improves both
performance and sample efficiency. Our metric outperforms the previous prompt
selection metrics with an average increase of 5% in accuracy and 10% in Pearson
correlation across 6 classification benchmarks
Multilingual Coreference Resolution in Multiparty Dialogue
Existing multiparty dialogue datasets for coreference resolution are nascent,
and many challenges are still unaddressed. We create a large-scale dataset,
Multilingual Multiparty Coref (MMC), for this task based on TV transcripts. Due
to the availability of gold-quality subtitles in multiple languages, we propose
reusing the annotations to create silver coreference data in other languages
(Chinese and Farsi) via annotation projection. On the gold (English) data,
off-the-shelf models perform relatively poorly on MMC, suggesting that MMC has
broader coverage of multiparty coreference than prior datasets. On the silver
data, we find success both using it for data augmentation and training from
scratch, which effectively simulates the zero-shot cross-lingual setting
Extraneousness-Aware Imitation Learning
Visual imitation learning provides an effective framework to learn skills
from demonstrations. However, the quality of the provided demonstrations
usually significantly affects the ability of an agent to acquire desired
skills. Therefore, the standard visual imitation learning assumes near-optimal
demonstrations, which are expensive or sometimes prohibitive to collect.
Previous works propose to learn from noisy demonstrations; however, the noise
is usually assumed to follow a context-independent distribution such as a
uniform or gaussian distribution. In this paper, we consider another crucial
yet underexplored setting -- imitation learning with task-irrelevant yet
locally consistent segments in the demonstrations (e.g., wiping sweat while
cutting potatoes in a cooking tutorial). We argue that such noise is common in
real world data and term them "extraneous" segments. To tackle this problem, we
introduce Extraneousness-Aware Imitation Learning (EIL), a self-supervised
approach that learns visuomotor policies from third-person demonstrations with
extraneous subsequences. EIL learns action-conditioned observation embeddings
in a self-supervised manner and retrieves task-relevant observations across
visual demonstrations while excluding the extraneous ones. Experimental results
show that EIL outperforms strong baselines and achieves comparable policies to
those trained with perfect demonstration on both simulated and real-world robot
control tasks. The project page can be found at
https://sites.google.com/view/eil-website.Comment: 7 pages, 6 figure
MGG: Accelerating Graph Neural Networks with Fine-grained intra-kernel Communication-Computation Pipelining on Multi-GPU Platforms
The increasing size of input graphs for graph neural networks (GNNs)
highlights the demand for using multi-GPU platforms. However, existing
multi-GPU GNN systems optimize the computation and communication individually
based on the conventional practice of scaling dense DNNs. For irregularly
sparse and fine-grained GNN workloads, such solutions miss the opportunity to
jointly schedule/optimize the computation and communication operations for
high-performance delivery. To this end, we propose MGG, a novel system design
to accelerate full-graph GNNs on multi-GPU platforms. The core of MGG is its
novel dynamic software pipeline to facilitate fine-grained
computation-communication overlapping within a GPU kernel. Specifically, MGG
introduces GNN-tailored pipeline construction and GPU-aware pipeline mapping to
facilitate workload balancing and operation overlapping. MGG also incorporates
an intelligent runtime design with analytical modeling and optimization
heuristics to dynamically improve the execution performance. Extensive
evaluation reveals that MGG outperforms state-of-the-art full-graph GNN systems
across various settings: on average 4.41X, 4.81X, and 10.83X faster than DGL,
MGG-UVM, and ROC, respectively
Mind2Web: Towards a Generalist Agent for the Web
We introduce Mind2Web, the first dataset for developing and evaluating
generalist agents for the web that can follow language instructions to complete
complex tasks on any website. Existing datasets for web agents either use
simulated websites or only cover a limited set of websites and tasks, thus not
suitable for generalist web agents. With over 2,000 open-ended tasks collected
from 137 websites spanning 31 domains and crowdsourced action sequences for the
tasks, Mind2Web provides three necessary ingredients for building generalist
web agents: 1) diverse domains, websites, and tasks, 2) use of real-world
websites instead of simulated and simplified ones, and 3) a broad spectrum of
user interaction patterns. Based on Mind2Web, we conduct an initial exploration
of using large language models (LLMs) for building generalist web agents. While
the raw HTML of real-world websites are often too large to be fed to LLMs, we
show that first filtering it with a small LM significantly improves the
effectiveness and efficiency of LLMs. Our solution demonstrates a decent level
of performance, even on websites or entire domains the model has never seen
before, but there is still a substantial room to improve towards truly
generalizable agents. We open-source our dataset, model implementation, and
trained models (https://osu-nlp-group.github.io/Mind2Web) to facilitate further
research on building a generalist agent for the web.Comment: website: https://osu-nlp-group.github.io/Mind2We
Analysis and Fault-Tolerant Control for Dual-Three-Phase PMSM Based on Virtual Healthy Model
Dual-three-phase permanent magnet synchronous machines (DTP-PMSMs) are famous for their fault-tolerant capability. However, the complex modeling, high copper loss, and torque ripple under postfault operation limit their further application. In this article, a fault-tolerant control (FTC) strategy is developed for DTP-PMSMs under the open-phase fault (OPF) with straightforward modeling and smooth output torque. The virtual healthy DTP-PMSM model, where the coordinate transformation, the modulation strategy, and the controller structure remain unchanged under OPF, is adopted in the proposed FTC scheme. And the current references are derived in sinusoidal waves with minimum copper loss. The inaccurate transmission of control signals under OPF is also focused on. Comprehensive theoretical analysis shows the relationship between the controller output voltage and the actual stator voltage should be considered in the proposed FTC strategy; otherwise, distortion in torque and current will be introduced. The voltage compensation is utilized to compensate for the voltage difference and ensure the smooth torque output. Besides, a quasi proportional resonance controller is designed to further suppress the residual torque ripple. The proposed strategy will not induce complex implementation and heavy computation burden. The simulation and experimental results prove the analysis and the effectiveness of the proposed strategy
Observation of giant nonreciprocal charge transport from quantum Hall edge states of single surface in topological insulator
Symmetry breaking in quantum materials is of great importance and leads to
novel nonreciprocal charge transport. The topological insulator system provides
a unique platform to study nonreciprocal charge transport due to the exotic
surface state. But it is typically small in magnitude because the contributions
from the top and bottom surface of topological insulator are usually opposite.
Here, we report the observation of giant nonreciprocal charge transport
mediated by the quantum Hall state in intrinsic topological insulator
Sn-Bi1.1Sb0.9Te2S devices, which is attributed to the coexistence of quantum
Hall states and Dirac surface states. A giant nonreciprocal coefficient of up
to 2.26*10^5 A^-1 is found, because only a single surface of topological
insulator contributes to the nonreciprocal charge transport. Our work not only
reveals the intrinsic properties of nonreciprocal charge transport in
topological insulators, but also paves the way for future electronic devices
Large Exchange Bias Effect and Coverage-Dependent Interfacial Coupling in CrI3/MnBi2Te4 van der Waals Heterostructures
Igniting interface magnetic ordering of magnetic topological insulators by
building a van der Waals heterostructure can help to reveal novel quantum
states and design functional devices. Here, we observe an interesting exchange
bias effect, indicating successful interfacial magnetic coupling, in
CrI3/MnBi2Te4 ferromagnetic insulator/antiferromagnetic topological insulator
(FMI/AFM-TI) heterostructure devices. The devices originally exhibit a negative
exchange bias field, which decays with increasing temperature and is unaffected
by the back-gate voltage. When we change the device configuration to be
half-covered by CrI3, the exchange bias becomes positive with a very large
exchange bias field exceeding 300 mT. Such sensitive manipulation is explained
by the competition between the FM and AFM coupling at the interface of CrI3 and
MnBi2Te4, pointing to coverage-dependent interfacial magnetic interactions. Our
work will facilitate the development of topological and antiferromagnetic
devices