Oceania
Pragmatic Reasoning Unlocks Quantifier Semantics for Foundation Models
Li, Yiyuan, Menon, Rakesh R., Ghosh, Sayan, Srivastava, Shashank
Generalized quantifiers (e.g., few, most) are used to indicate the proportions predicates are satisfied (for example, some apples are red). One way to interpret quantifier semantics is to explicitly bind these satisfactions with percentage scopes (e.g., 30%-40% of apples are red). This approach can be helpful for tasks like logic formalization and surface-form quantitative reasoning (Gordon and Schubert, 2010; Roy et al., 2015). However, it remains unclear if recent foundation models possess this ability, as they lack direct training signals. To explore this, we introduce QuRe, a crowd-sourced dataset of human-annotated generalized quantifiers in Wikipedia sentences featuring percentage-equipped predicates. We explore quantifier comprehension in language models using PRESQUE, a framework that combines natural language inference and the Rational Speech Acts framework. Experimental results on the HVD dataset and QuRe illustrate that PRESQUE, employing pragmatic reasoning, performs 20% better than a literal reasoning baseline when predicting quantifier percentage scopes, with no additional training required.
Learning to Select SAT Encodings for Pseudo-Boolean and Linear Integer Constraints
Ulrich-Oltean, Felix, Nightingale, Peter, Walker, James Alfred
Many constraint satisfaction and optimisation problems can be solved effectively by encoding them as instances of the Boolean Satisfiability problem (SAT). However, even the simplest types of constraints have many encodings in the literature with widely varying performance, and the problem of selecting suitable encodings for a given problem instance is not trivial. We explore the problem of selecting encodings for pseudo-Boolean and linear constraints using a supervised machine learning approach. We show that it is possible to select encodings effectively using a standard set of features for constraint problems; however we obtain better performance with a new set of features specifically designed for the pseudo-Boolean and linear constraints. In fact, we achieve good results when selecting encodings for unseen problem classes. Our results compare favourably to AutoFolio when using the same feature set. We discuss the relative importance of instance features to the task of selecting the best encodings, and compare several variations of the machine learning method.
Eigensubspace of Temporal-Difference Dynamics and How It Improves Value Approximation in Reinforcement Learning
He, Qiang, Zhou, Tianyi, Fang, Meng, Maghsudi, Setareh
We propose a novel value approximation method, namely "Eigensubspace Regularized Critic (ERC)" for deep reinforcement learning (RL). ERC is motivated by an analysis of the dynamics of Q-value approximation error in the Temporal-Difference (TD) method, which follows a path defined by the 1-eigensubspace of the transition kernel associated with the Markov Decision Process (MDP). It reveals a fundamental property of TD learning that has remained unused in previous deep RL approaches. In ERC, we propose a regularizer that guides the approximation error tending towards the 1-eigensubspace, resulting in a more efficient and stable path of value approximation. Moreover, we theoretically prove the convergence of the ERC method. Besides, theoretical analysis and experiments demonstrate that ERC effectively reduces the variance of value functions. Among 26 tasks in the DMControl benchmark, ERC outperforms state-of-the-art methods for 20. Besides, it shows significant advantages in Q-value approximation and variance reduction. Our code is available at https://sites.google.com/view/erc-ecml23/.
More PAC-Bayes bounds: From bounded losses, to losses with general tail behaviors, to anytime-validity
Rodríguez-Gálvez, Borja, Thobaben, Ragnar, Skoglund, Mikael
In this paper, we present new high-probability PAC-Bayes bounds for different types of losses. Firstly, for losses with a bounded range, we recover a strengthened version of Catoni's bound that holds uniformly for all parameter values. This leads to new fast rate and mixed rate bounds that are interpretable and tighter than previous bounds in the literature. In particular, the fast rate bound is equivalent to the Seeger--Langford bound. Secondly, for losses with more general tail behaviors, we introduce two new parameter-free bounds: a PAC-Bayes Chernoff analogue when the loss' cumulative generating function is bounded, and a bound when the loss' second moment is bounded. These two bounds are obtained using a new technique based on a discretization of the space of possible events for the "in probability" parameter optimization problem. This technique is both simpler and more general than previous approaches optimizing over a grid on the parameters' space. Finally, we extend all previous results to anytime-valid bounds using a simple technique applicable to any existing bound.
Hierarchical clustering with dot products recovers hidden tree structure
Gray, Annie, Modell, Alexander, Rubin-Delanchy, Patrick, Whiteley, Nick
In this paper we offer a new perspective on the well established agglomerative clustering algorithm, focusing on recovery of hierarchical structure. We recommend a simple variant of the standard algorithm, in which clusters are merged by maximum average dot product and not, for example, by minimum distance or within-cluster variance. We demonstrate that the tree output by this algorithm provides a bona fide estimate of generative hierarchical structure in data, under a generic probabilistic graphical model. The key technical innovations are to understand how hierarchical information in this model translates into tree geometry which can be recovered from data, and to characterise the benefits of simultaneously growing sample size and data dimension. We demonstrate superior tree recovery performance with real data over existing approaches such as UPGMA, Ward's method, and HDBSCAN.
Sam Bankman-Fried Is Going to Prison. What About Gabe Bankman-Fried?
On Thursday, jurors convicted former crypto mogul Sam Bankman-Fried of defrauding his customers out of as much as $10 billion. He will likely spend the rest of his 30s--and possibly his 40s, 50s, and 60s--in prison. The judge is expected to sentence him in March. As former confidants and close friends testified against him during his monthlong trial, Bankman-Fried's parents, Joseph and Barbara, showed up day after day to support their son, whose crypto exchange FTX imploded late last year. The Stanford Law professors' hand gestures and facial expressions played prominently into journalists' recounts of the proceedings, offering the real-life version of the cutaway shot integral to any courtroom TV show.
TechScape: Why Sunak's 'vanity jamboree' on AI safety was actually … a success
For Max Tegmark, last week's artificial intelligence summit at Bletchley Park was an emotional moment. The MIT professor and AI researcher was behind a letter this year calling for a pause in development of advanced systems. It didn't happen, but it was a crucial contribution to the political and academic momentum that resulted in the Bletchley gathering. "[The summit] has actually made me more optimistic. It really has superseded my expectations," he told me.
Impact of HPO on AutoML Forecasting Ensembles
Due to this uncertainty over which models will perform best, it is common place in the forecasting space that domain experts and data scientists have to experiment with several methods before they find one that works acceptably well on a particular problem. This exploration process can be time and resource consuming and is not always practical, due to the plethora of unsolved forecasting problems as well as the scarcity of domain experts and data scientists. In recent years, Automated Machine Learning (AutoML) has become more popular, allowing non-technical users to solve machine learning problems without in depth knowledge about the underlying methodology, filling in for the lack of available data scientists through automation [5]. In forecasting there are several approaches to AutoML, one of them being the established method of using ensemble learning and aggregation of forecasts [6]. This has seen a recent increase in attention, with the top performing models in the M4 Competition [7] being of this nature [8]. Ensembling, can be conceptualised as the automation of the previously manual step of exploring the performance of various algorithms on a given problem and selecting the best one or a combination of models. This, however, does not address another important aspect of data science which is the selection of good hyperparameters, leading to better performance of a model trained using a particular algorithm. The combination of ensemble learning and hyperparameter tuning in an AutoML forecasting setup will be discussed in this paper.
The AI Ghostwriter Effect: When Users Do Not Perceive Ownership of AI-Generated Text But Self-Declare as Authors
Draxler, Fiona, Werner, Anna, Lehmann, Florian, Hoppe, Matthias, Schmidt, Albrecht, Buschek, Daniel, Welsch, Robin
Human-AI interaction in text production increases complexity in authorship. In two empirical studies (n1 = 30 & n2 = 96), we investigate authorship and ownership in human-AI collaboration for personalized language generation. We show an AI Ghostwriter Effect: Users do not consider themselves the owners and authors of AI-generated text but refrain from publicly declaring AI authorship. Personalization of AI-generated texts did not impact the AI Ghostwriter Effect, and higher levels of participants' influence on texts increased their sense of ownership. Participants were more likely to attribute ownership to supposedly human ghostwriters than AI ghostwriters, resulting in a higher ownership-authorship discrepancy for human ghostwriters. Rationalizations for authorship in AI ghostwriters and human ghostwriters were similar. We discuss how our findings relate to psychological ownership and human-AI interaction to lay the foundations for adapting authorship frameworks and user interfaces in AI in text-generation tasks.
Graph Construction using Principal Axis Trees for Simple Graph Convolution
Alshammari, Mashaan, Stavrakakis, John, Ahmed, Adel F., Takatsuka, Masahiro
Graph Neural Networks (GNNs) are increasingly becoming the favorite method for graph learning. They exploit the semi-supervised nature of deep learning, and they bypass computational bottlenecks associated with traditional graph learning methods. In addition to the feature matrix $X$, GNNs need an adjacency matrix $A$ to perform feature propagation. In many cases, the adjacency matrix $A$ is missing. We introduce a graph construction scheme that constructs the adjacency matrix $A$ using unsupervised and supervised information. Unsupervised information characterizes the neighborhood around points. We used Principal Axis trees (PA-trees) as a source for unsupervised information, where we create edges between points falling onto the same leaf node. For supervised information, we used the concept of penalty and intrinsic graphs. A penalty graph connects points with different class labels, whereas an intrinsic graph connects points with the same class labels. We used the penalty and intrinsic graphs to remove or add edges to the graph constructed via PA-tree. We tested this graph construction scheme on two well-known GNNs: 1) Graph Convolutional Network (GCN) and 2) Simple Graph Convolution (SGC). The experiments show that it is better to use SGC because it is faster and delivers better or the same results as GCN. We also test the effect of oversmoothing on both GCN and SGC. We found out that the level of smoothing has to be carefully selected for SGC to avoid oversmoothing.