South America
Fourier-RNNs for Modelling Noisy Physics Data
Gopakumar, Vignesh, Pamela, Stanislas, Zanisi, Lorenzo
Classical sequential models employed in time-series prediction rely on learning the mappings from the past to the future instances by way of a hidden state. The Hidden states characterise the historical information and encode the required temporal dependencies. However, most existing sequential models operate within finite-dimensional Euclidean spaces which offer limited functionality when employed in modelling physics relevant data. Alternatively recent work with neural operator learning within the Fourier space has shown efficient strategies for parameterising Partial Differential Equations (PDE). In this work, we propose a novel sequential model, built to handle Physics relevant data by way of amalgamating the conventional RNN architecture with that of the Fourier Neural Operators (FNO). The Fourier-RNN allows for learning the mappings from the input to the output as well as to the hidden state within the Fourier space associated with the temporal data. While the Fourier-RNN performs identical to the FNO when handling PDE data, it outperforms the FNO and the conventional RNN when deployed in modelling noisy, non-Markovian data.
Biases in Scholarly Recommender Systems: Impact, Prevalence, and Mitigation
Fรคrber, Michael, Coutinho, Melissa, Yuan, Shuzhou
With the remarkable increase in the number of scientific entities such as publications, researchers, and scientific topics, and the associated information overload in science, academic recommender systems have become increasingly important for millions of researchers and science enthusiasts. However, it is often overlooked that these systems are subject to various biases. In this article, we first break down the biases of academic recommender systems and characterize them according to their impact and prevalence. In doing so, we distinguish between biases originally caused by humans and biases induced by the recommender system. Second, we provide an overview of methods that have been used to mitigate these biases in the scholarly domain. Based on this, third, we present a framework that can be used by researchers and developers to mitigate biases in scholarly recommender systems and to evaluate recommender systems fairly. Finally, we discuss open challenges and possible research directions related to scholarly biases.
Reinforcement Learning with Almost Sure Constraints
Castellano, Agustin, Min, Hancheng, Bazerque, Juan, Mallada, Enrique
In this work we address the problem of finding feasible policies for Constrained Markov Decision Processes under probability one constraints. We argue that stationary policies are not sufficient for solving this problem, and that a rich class of policies can be found by endowing the controller with a scalar quantity, so called budget, that tracks how close the agent is to violating the constraint. We show that the minimal budget required to act safely can be obtained as the smallest fixed point of a Bellman-like operator, for which we analyze its convergence properties. We also show how to learn this quantity when the true kernel of the Markov decision process is not known, while providing sample-complexity bounds. The utility of knowing this minimal budget relies in that it can aid in the search of optimal or near-optimal policies by shrinking down the region of the state space the agent must navigate. Simulations illustrate the different nature of probability one constraints against the typically used constraints in expectation.
Learning to Act Safely with Limited Exposure and Almost Sure Certainty
Castellano, Agustin, Min, Hancheng, Bazerque, Juan, Mallada, Enrique
This paper puts forward the concept that learning to take safe actions in unknown environments, even with probability one guarantees, can be achieved without the need for an unbounded number of exploratory trials. This is indeed possible, provided that one is willing to navigate trade-offs between optimality, level of exposure to unsafe events, and the maximum detection time of unsafe actions. We illustrate this concept in two complementary settings. We first focus on the canonical multi-armed bandit problem and study the intrinsic trade-offs of learning safety in the presence of uncertainty. Under mild assumptions on sufficient exploration, we provide an algorithm that provably detects all unsafe machines in an (expected) finite number of rounds. The analysis also unveils a trade-off between the number of rounds needed to secure the environment and the probability of discarding safe machines. We then consider the problem of finding optimal policies for a Markov Decision Process (MDP) with almost sure constraints. We show that the action-value function satisfies a barrier-based decomposition which allows for the identification of feasible policies independently of the reward process. Using this decomposition, we develop a Barrier-learning algorithm, that identifies such unsafe state-action pairs in a finite expected number of steps. Our analysis further highlights a trade-off between the time lag for the underlying MDP necessary to detect unsafe actions, and the level of exposure to unsafe events. Simulations corroborate our theoretical findings, further illustrating the aforementioned trade-offs, and suggesting that safety constraints can speed up the learning process.
Do Language Models Plagiarize?
Lee, Jooyoung, Le, Thai, Chen, Jinghui, Lee, Dongwon
In this work, therefore, we study three types of plagiarism (i.e., verbatim, paraphrase, and idea) among GPT-2 generated texts, Language Models (LMs) have become core elements of Natural in comparison to its training data, and further analyze the plagiarism Language Processing (NLP) solutions, excelling in a wide range of patterns of fine-tuned LMs with domain-specific corpora which are tasks such as natural language generation (NLG), speech recognition, extensively used in practice. Our results suggest that (1) three types machine translation, and question answering. The development of plagiarism widely exist in LMs beyond memorization, (2) both of large-scale text corpora (generally scraped from the Web) has size and decoding methods of LMs are strongly associated with the enabled researchers to train increasingly large-scale LMs. Especially, degrees of plagiarism they exhibit, and (3) fine-tuned LMs' plagiarism large-scale LMs have demonstrated unprecedented performance on patterns vary based on their corpus similarity and homogeneity. NLG such that LM-generated texts routinely show more novel and Given that a majority of LMs' training data is scraped from the Web interesting stories than human writings do [35], and the distinction without informing content owners, their reiteration of words, phrases, between machine-authored and human-written texts has become and even core ideas from training sets into generated texts has ethical non-trivial [52, 53]. As a result, there has been a significant increase implications. Their patterns are likely to exacerbate as both in the use of LMs in user-facing products and critical applications.
Discriminative Radial Domain Adaptation
Huang, Zenan, Wen, Jun, Chen, Siheng, Zhu, Linchao, Zheng, Nenggan
Domain adaptation methods reduce domain shift typically by learning domain-invariant features. Most existing methods are built on distribution matching, e.g., adversarial domain adaptation, which tends to corrupt feature discriminability. In this paper, we propose Discriminative Radial Domain Adaptation (DRDA) which bridges source and target domains via a shared radial structure. It's motivated by the observation that as the model is trained to be progressively discriminative, features of different categories expand outwards in different directions, forming a radial structure. We show that transferring such an inherently discriminative structure would enable to enhance feature transferability and discriminability simultaneously. Specifically, we represent each domain with a global anchor and each category a local anchor to form a radial structure and reduce domain shift via structure matching. It consists of two parts, namely isometric transformation to align the structure globally and local refinement to match each category. To enhance the discriminability of the structure, we further encourage samples to cluster close to the corresponding local anchors based on optimal-transport assignment. Extensively experimenting on multiple benchmarks, our method is shown to consistently outperforms state-of-the-art approaches on varied tasks, including the typical unsupervised domain adaptation, multi-source domain adaptation, domain-agnostic learning, and domain generalization.
Jobs of the Future: ChatGPT, AI Will Create Careers That Need Humans
Since ChatGPT took the world by storm last fall, people have been in a frenzy debating the impact artificial intelligence and other new automated technology will have on America's job market. The "robots are taking our jobs" narrative was further boosted by viral videos showing new, "fully automated" McDonald's and Taco Bell restaurants. The knee-jerk reaction to these videos is to say that robots are coming for our jobs, but while AI and other kinds of automation have progressed, that doesn't mean they're necessarily eliminating jobs. Instead, the new tech is simply changing how we work and what kinds of jobs exist. Automation technology has ushered in a fleet of secret workers behind screens, machines, and smiling robot faces.
Could ChatGPT replace Google? Experts weigh in on who will win the race to an AI search engine
So far, there doesn't seem to be an awful lot that ChatGPT โ the chatbot powered by artificial intelligence (AI) โ can't do. It has been used to pass exams, deliver a sermon, write software and give relationship advice -- to name just a handful of its functions. The bot is currently free for anyone to use, meaning that lots of users have been asking it questions to get the information they need in their daily lives. Since the turn of the millennium, this job has been primarily reserved for Google -- the world's most popular search engine and its $149 billion (ยฃ120 billion) business. And, if so, which of the warring tech giants will get there first?
Geodesic Graph Neural Network for Efficient Graph Representation Learning
Kong, Lecheng, Chen, Yixin, Zhang, Muhan
Graph Neural Networks (GNNs) have recently been applied to graph learning tasks and achieved state-of-the-art (SOTA) results. However, many competitive methods run GNNs multiple times with subgraph extraction and customized labeling to capture information that is hard for normal GNNs to learn. Such operations are time-consuming and do not scale to large graphs. In this paper, we propose an efficient GNN framework called Geodesic GNN (GDGNN) that requires only one GNN run and injects conditional relationships between nodes into the model without labeling. This strategy effectively reduces the runtime of subgraph methods. Specifically, we view the shortest paths between two nodes as the spatial graph context of the neighborhood around them. The GNN embeddings of nodes on the shortest paths are used to generate geodesic representations. Conditioned on the geodesic representations, GDGNN can generate node, link, and graph representations that carry much richer structural information than plain GNNs. We theoretically prove that GDGNN is more powerful than plain GNNs. We present experimental results to show that GDGNN achieves highly competitive performance with SOTA GNN models on various graph learning tasks while taking significantly less time.
An unsupervised learning approach for predicting wind farm power and downstream wakes using weather patterns
Clare, Mariana C A, Warder, Simon C, Neal, Robert, Bhaskaran, B, Piggott, Matthew D
Wind energy resource assessment typically requires numerical models, but such models are too computationally intensive to consider multi-year timescales. Increasingly, unsupervised machine learning techniques are used to identify a small number of representative weather patterns to simulate long-term behaviour. Here we develop a novel wind energy workflow that for the first time combines weather patterns derived from unsupervised clustering techniques with numerical weather prediction models (here WRF) to obtain efficient and accurate long-term predictions of power and downstream wakes from an entire wind farm. We use ERA5 reanalysis data clustering not only on low altitude pressure but also, for the first time, on the more relevant variable of wind velocity. We also compare the use of large-scale and local-scale domains for clustering. A WRF simulation is run at each of the cluster centres and the results are aggregated using a novel post-processing technique. By applying our workflow to two different regions, we show that our long-term predictions agree with those from a year of WRF simulations but require less than 2% of the computational time. The most accurate results are obtained when clustering on wind velocity. Moreover, clustering over the Europe-wide domain is sufficient for predicting wind farm power output, but downstream wake predictions benefit from the use of smaller domains. Finally, we show that these downstream wakes can affect the local weather patterns. Our approach facilitates multi-year predictions of power output and downstream farm wakes, by providing a fast, accurate and flexible methodology that is applicable to any global region. Moreover, these accurate long-term predictions of downstream wakes provide the first tool to help mitigate the effects of wind energy loss downstream of wind farms, since they can be used to determine optimum wind farm locations.