79 research outputs found
Lifelong Sequence Generation with Dynamic Module Expansion and Adaptation
Lifelong sequence generation (LSG), a problem in continual learning, aims to
continually train a model on a sequence of generation tasks to learn constantly
emerging new generation patterns while avoiding the forgetting of previous
knowledge. Existing LSG methods mainly focus on maintaining old knowledge while
paying little attention to knowledge transfer across tasks. In contrast, humans
can better learn new tasks by leveraging previously acquired knowledge from
similar tasks. Inspired by the learning paradigm of humans, we propose Dynamic
Module Expansion and Adaptation (DMEA), which enables the model to dynamically
determine the architecture for acquiring new knowledge based on task
correlation and select the most similar previous tasks to facilitate adaptation
to new tasks. In addition, as the learning process can easily be biased towards
the current task which might cause more severe forgetting of previously learned
knowledge, we propose dynamic gradient scaling to balance the learning of the
current task and replayed tasks. With extensive experiments, we demonstrate
that DMEA can consistently outperform existing methods in different LSG
settings
Learning to Initialize: Can Meta Learning Improve Cross-task Generalization in Prompt Tuning?
Prompt tuning (PT) which only tunes the embeddings of an additional sequence
of tokens per task, keeping the pre-trained language model (PLM) frozen, has
shown remarkable performance in few-shot learning. Despite this, PT has been
shown to rely heavily on good initialization of the prompt embeddings. In this
work, we study meta prompt tuning (MPT) to systematically explore how
meta-learning can help improve (if it can) cross-task generalization in PT
through learning to initialize the prompt embeddings from other relevant tasks.
We empirically analyze a representative set of meta learning algorithms in a
wide range of adaptation settings with different source/target task
configurations on a large set of few-shot tasks. With extensive experiments and
analysis, we demonstrate the effectiveness of MPT. We find the improvement to
be significant particularly on classification tasks. For other kinds of tasks
such as question answering, we observe that while MPT can outperform PT in most
cases, it does not always outperform multi-task learning. We further provide an
in-depth analysis from the perspective of task similarity
In-Context Learning with Iterative Demonstration Selection
Spurred by advancements in scale, large language models (LLMs) have
demonstrated strong few-shot learning ability via in-context learning (ICL).
However, the performance of ICL has been shown to be highly sensitive to the
selection of few-shot demonstrations. Selecting the most suitable examples as
context remains an ongoing challenge and an open problem. Existing literature
has highlighted the importance of selecting examples that are diverse or
semantically similar to the test sample while ignoring the fact that the
optimal selection dimension, i.e., diversity or similarity, is task-specific.
Leveraging the merits of both dimensions, we propose Iterative Demonstration
Selection (IDS). Using zero-shot chain-of-thought reasoning (Zero-shot-CoT),
IDS iteratively selects examples that are diverse but still strongly correlated
with the test sample as ICL demonstrations. Specifically, IDS applies
Zero-shot-CoT to the test sample before demonstration selection. The output
reasoning path is then used to choose demonstrations that are prepended to the
test sample for inference. The generated answer is accompanied by its
corresponding reasoning path for extracting a new set of demonstrations in the
next iteration. After several iterations, IDS adopts majority voting to obtain
the final result. Through extensive experiments on tasks including commonsense
reasoning, question answering, topic classification, and sentiment analysis, we
demonstrate that IDS can consistently outperform existing ICL demonstration
selection methods
Is ChatGPT a General-Purpose Natural Language Processing Task Solver?
Spurred by advancements in scale, large language models (LLMs) have
demonstrated the ability to perform a variety of natural language processing
(NLP) tasks zero-shot -- i.e., without adaptation on downstream data. Recently,
the debut of ChatGPT has drawn a great deal of attention from the natural
language processing (NLP) community due to the fact that it can generate
high-quality responses to human input and self-correct previous mistakes based
on subsequent conversations. However, it is not yet known whether ChatGPT can
serve as a generalist model that can perform many NLP tasks zero-shot. In this
work, we empirically analyze the zero-shot learning ability of ChatGPT by
evaluating it on 20 popular NLP datasets covering 7 representative task
categories. With extensive empirical studies, we demonstrate both the
effectiveness and limitations of the current version of ChatGPT. We find that
ChatGPT performs well on many tasks favoring reasoning capabilities (e.g.,
arithmetic reasoning) while it still faces challenges when solving specific
tasks such as sequence tagging. We additionally provide in-depth analysis
through qualitative case studies
Hearing Lips in Noise : Universal Viseme-Phoneme Mapping and Transfer for Robust Audio-Visual Speech Recognition
PreprintPublisher PD
Shaping a subwavelength needle with ultra-long focal length by focusing azimuthally polarized light
10.1038/srep09977Scientific Reports
Solution and type curves for the seepage model of the water-bearing coalbed with leakage recharge
To analyze the effects of the leakage recharge of the aquifer on the initial dewatering of coalbed methane wells, the mathematical seepage model of water in the coalbed considering the aquifer leakage was established by using the leakage coefficient according to the unsteady seepage theory. The model was solved after Laplace transform and the Stehfest numerical reverse inversion was used to obtain the solution in right space. Then, the log-log type curves of pressure and pressure derivative were created with new combinations of parameters. Based on the natural seepage mechanism, the influence of aquifer leakage on curve shape was judged. It is found that the radial flow ends earlier as the leakage coefficient increases. Moreover, it was proposed to obtain reservoir permeability, skin factor, and leakage coefficient by using type curve matching. The type curves are useful for quantitatively evaluating the level of leakage, thereby guiding the adjustment of the following production system for CBM wells.Este estudio estableció el modelo matemático de filtración de agua en una capa carbonífera al estimar la salida acuífera con el uso del coeficiente de fuga, de acuerdo con la teoría de filtración inestable, para analizar los efectos en la recarga de pérdida de fluidos de un acuífero en el drenado inicial para pozos de gas metano. El modelo se resolvió tras usar la transformación Laplace y la inversión numérica Stehfest para encontrar la respuesta en el lugar indicado. Luego, se creó la representación algorítmica de la presión y la presión derivativa con nuevas combinaciones de parámetros. Se evaluó la influencia de la pérdida de fluido del acuífero en la forma de la curva con base al mecanismo físico de filtración. Se estableció que el flujo radial finaliza antes de que el coeficiente de pérdida de fluido se incremente. Además, se propone el uso de la curva tipo correspondiente para obtener la permeabilidad del reservorio, el factor de daño y el coeficiente de pérdida de fluido. Las curvas tipo son útiles para evaluar cuantitativamente el nivel de la pérdida de fluido, y de esta manera guiar el ajuste de un sistema de producción consecuente para pozos de gas metano de carbón
Retrieving Multimodal Information for Augmented Generation: A Survey
As Large Language Models (LLMs) become popular, there emerged an important
trend of using multimodality to augment the LLMs' generation ability, which
enables LLMs to better interact with the world. However, there lacks a unified
perception of at which stage and how to incorporate different modalities. In
this survey, we review methods that assist and augment generative models by
retrieving multimodal knowledge, whose formats range from images, codes,
tables, graphs, to audio. Such methods offer a promising solution to important
concerns such as factuality, reasoning, interpretability, and robustness. By
providing an in-depth review, this survey is expected to provide scholars with
a deeper understanding of the methods' applications and encourage them to adapt
existing techniques to the fast-growing field of LLMs
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