107,284 research outputs found
A hypothesis on improving foreign accents by optimizing variability in vocal learning brain circuits
Rapid vocal motor learning is observed when acquiring a language in early childhood, or learning to speak another language later in life. Accurate pronunciation is one of the hardest things for late learners to master and they are almost always left with a non-native accent. Here I propose a novel hypothesis that this accent could be improved by optimizing variability in vocal learning brain circuits during learning. Much of the neurobiology of human vocal motor learning has been inferred from studies on songbirds. Jarvis (2004) proposed the hypothesis that as in songbirds there are two pathways in humans: one for learning speech (the striatal vocal learning pathway), and one for production of previously learnt speech (the motor pathway). Learning new motor sequences necessary for accurate non-native pronunciation is challenging and I argue that in late learners of a foreign language the vocal learning pathway becomes inactive prematurely. The motor pathway is engaged once again and learners maintain their original native motor patterns for producing speech, resulting in speaking with a foreign accent. Further, I argue that variability in neural activity within vocal motor circuitry generates vocal variability that supports accurate non-native pronunciation. Recent theoretical and experimental work on motor learning suggests that variability in the motor movement is necessary for the development of expertise. I propose that there is little trial-by-trial variability when using the motor pathway. When using the vocal learning pathway variability gradually increases, reflecting an exploratory phase in which learners try out different ways of pronouncing words, before decreasing and stabilizing once the ‘best’ performance has been identified. The hypothesis proposed here could be tested using behavioral interventions that optimize variability and engage the vocal learning pathway for longer, with the prediction that this would allow learners to develop new motor patterns that result in more native-like pronunciation
Contrastive Preference Learning: Learning from Human Feedback without RL
Reinforcement Learning from Human Feedback (RLHF) has emerged as a popular
paradigm for aligning models with human intent. Typically RLHF algorithms
operate in two phases: first, use human preferences to learn a reward function
and second, align the model by optimizing the learned reward via reinforcement
learning (RL). This paradigm assumes that human preferences are distributed
according to reward, but recent work suggests that they instead follow the
regret under the user's optimal policy. Thus, learning a reward function from
feedback is not only based on a flawed assumption of human preference, but also
leads to unwieldy optimization challenges that stem from policy gradients or
bootstrapping in the RL phase. Because of these optimization challenges,
contemporary RLHF methods restrict themselves to contextual bandit settings
(e.g., as in large language models) or limit observation dimensionality (e.g.,
state-based robotics). We overcome these limitations by introducing a new
family of algorithms for optimizing behavior from human feedback using the
regret-based model of human preferences. Using the principle of maximum
entropy, we derive Contrastive Preference Learning (CPL), an algorithm for
learning optimal policies from preferences without learning reward functions,
circumventing the need for RL. CPL is fully off-policy, uses only a simple
contrastive objective, and can be applied to arbitrary MDPs. This enables CPL
to elegantly scale to high-dimensional and sequential RLHF problems while being
simpler than prior methods.Comment: Code released at https://github.com/jhejna/cpl. Edited 10/23 only to
fix typo in the titl
A Comprehensive Survey of Deep Learning in Remote Sensing: Theories, Tools and Challenges for the Community
In recent years, deep learning (DL), a re-branding of neural networks (NNs),
has risen to the top in numerous areas, namely computer vision (CV), speech
recognition, natural language processing, etc. Whereas remote sensing (RS)
possesses a number of unique challenges, primarily related to sensors and
applications, inevitably RS draws from many of the same theories as CV; e.g.,
statistics, fusion, and machine learning, to name a few. This means that the RS
community should be aware of, if not at the leading edge of, of advancements
like DL. Herein, we provide the most comprehensive survey of state-of-the-art
RS DL research. We also review recent new developments in the DL field that can
be used in DL for RS. Namely, we focus on theories, tools and challenges for
the RS community. Specifically, we focus on unsolved challenges and
opportunities as it relates to (i) inadequate data sets, (ii)
human-understandable solutions for modelling physical phenomena, (iii) Big
Data, (iv) non-traditional heterogeneous data sources, (v) DL architectures and
learning algorithms for spectral, spatial and temporal data, (vi) transfer
learning, (vii) an improved theoretical understanding of DL systems, (viii)
high barriers to entry, and (ix) training and optimizing the DL.Comment: 64 pages, 411 references. To appear in Journal of Applied Remote
Sensin
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