Education
L3DMC: Lifelong Learning using Distillation via Mixed-Curvature Space
Roy, Kaushik, Moghadam, Peyman, Harandi, Mehrtash
The performance of a lifelong learning (L3) model degrades when it is trained on a series of tasks, as the geometrical formation of the embedding space changes while learning novel concepts sequentially. The majority of existing L3 approaches operate on a fixed-curvature (e.g., zero-curvature Euclidean) space that is not necessarily suitable for modeling the complex geometric structure of data. Furthermore, the distillation strategies apply constraints directly on low-dimensional embeddings, discouraging the L3 model from learning new concepts by making the model highly stable. To address the problem, we propose a distillation strategy named L3DMC that operates on mixed-curvature spaces to preserve the already-learned knowledge by modeling and maintaining complex geometrical structures. We propose to embed the projected low dimensional embedding of fixed-curvature spaces (Euclidean and hyperbolic) to higher-dimensional Reproducing Kernel Hilbert Space (RKHS) using a positive-definite kernel function to attain rich representation. Afterward, we optimize the L3 model by minimizing the discrepancies between the new sample representation and the subspace constructed using the old representation in RKHS. L3DMC is capable of adapting new knowledge better without forgetting old knowledge as it combines the representation power of multiple fixed-curvature spaces and is performed on higher-dimensional RKHS. Thorough experiments on three benchmarks demonstrate the effectiveness of our proposed distillation strategy for medical image classification in L3 settings. Our code implementation is publicly available at https://github.com/csiro-robotics/L3DMC.
Collective behavior from surprise minimization
Heins, Conor, Millidge, Beren, da Costa, Lancelot, Mann, Richard, Friston, Karl, Couzin, Iain
Collective motion is ubiquitous in nature; groups of animals, such as fish, birds, and ungulates appear to move as a whole, exhibiting a rich behavioral repertoire that ranges from directed movement to milling to disordered swarming. Typically, such macroscopic patterns arise from decentralized, local interactions among constituent components (e.g., individual fish in a school). Preeminent models of this process describe individuals as self-propelled particles, subject to self-generated motion and 'social forces' such as short-range repulsion and long-range attraction or alignment. However, organisms are not particles; they are probabilistic decision-makers. Here, we introduce an approach to modelling collective behavior based on active inference. This cognitive framework casts behavior as the consequence of a single imperative: to minimize surprise. We demonstrate that many empirically-observed collective phenomena, including cohesion, milling and directed motion, emerge naturally when considering behavior as driven by active Bayesian inference -- without explicitly building behavioral rules or goals into individual agents. Furthermore, we show that active inference can recover and generalize the classical notion of social forces as agents attempt to suppress prediction errors that conflict with their expectations. By exploring the parameter space of the belief-based model, we reveal non-trivial relationships between the individual beliefs and group properties like polarization and the tendency to visit different collective states. We also explore how individual beliefs about uncertainty determine collective decision-making accuracy. Finally, we show how agents can update their generative model over time, resulting in groups that are collectively more sensitive to external fluctuations and encode information more robustly.
ChiPFormer: Transferable Chip Placement via Offline Decision Transformer
Lai, Yao, Liu, Jinxin, Tang, Zhentao, Wang, Bin, Hao, Jianye, Luo, Ping
Placement is a critical step in modern chip design, aiming to determine the positions of circuit modules on the chip canvas. Recent works have shown that reinforcement learning (RL) can improve human performance in chip placement. However, such an RL-based approach suffers from long training time and low transfer ability in unseen chip circuits. To resolve these challenges, we cast the chip placement as an offline RL formulation and present ChiPFormer that enables learning a transferable placement policy from fixed offline data. ChiPFormer has several advantages that prior arts do not have. First, ChiPFormer can exploit offline placement designs to learn transferable policies more efficiently in a multi-task setting. Second, ChiPFormer can promote effective finetuning for unseen chip circuits, reducing the placement runtime from hours to minutes. Third, extensive experiments on 32 chip circuits demonstrate that ChiPFormer achieves significantly better placement quality while reducing the runtime by 10x compared to recent state-of-the-art approaches in both public benchmarks and realistic industrial tasks. The deliverables are released at https://sites.google.com/view/chipformer/home.
Continual Multimodal Knowledge Graph Construction
Chen, Xiang, Zhang, Ningyu, Zhang, Jintian, Wang, Xiaohan, Wu, Tongtong, Chen, Xi, Wang, Yongheng, Chen, Huajun
Multimodal Knowledge Graph Construction (MKGC) involves creating structured representations of entities and relations using multiple modalities, such as text and images. However, existing MKGC models face challenges in handling the addition of new entities and relations in dynamic real-world scenarios. The current continual setting for knowledge graph construction mainly focuses on entity and relation extraction from text data, overlooking other multimodal sources. Therefore, there arises the need to explore the challenge of continual MKGC to address the phenomenon of catastrophic forgetting and ensure the retention of past knowledge extracted from different forms of data. This research focuses on investigating this complex topic by developing lifelong MKGC benchmark datasets. Based on the empirical findings that several typical MKGC models, when trained on multimedia data, might unexpectedly underperform compared to those solely utilizing textual resources in a continual setting, we propose a Lifelong MultiModal Consistent Transformer Framework (LMC) for continual MKGC, which plays the strengths of the consistent multimodal optimization in continual learning and leads to a better stability-plasticity trade-off. Our experiments demonstrate the superior performance of our method over prevailing continual learning techniques or multimodal approaches in dynamic scenarios. Code and datasets can be found at https://github.com/zjunlp/ContinueMKGC.
(Local) Differential Privacy has NO Disparate Impact on Fairness
Arcolezi, Hรฉber H., Makhlouf, Karima, Palamidessi, Catuscia
In recent years, Local Differential Privacy (LDP), a robust privacy-preserving methodology, has gained widespread adoption in real-world applications. With LDP, users can perturb their data on their devices before sending it out for analysis. However, as the collection of multiple sensitive information becomes more prevalent across various industries, collecting a single sensitive attribute under LDP may not be sufficient. Correlated attributes in the data may still lead to inferences about the sensitive attribute. This paper empirically studies the impact of collecting multiple sensitive attributes under LDP on fairness. We propose a novel privacy budget allocation scheme that considers the varying domain size of sensitive attributes. This generally led to a better privacy-utility-fairness trade-off in our experiments than the state-of-art solution. Our results show that LDP leads to slightly improved fairness in learning problems without significantly affecting the performance of the models. We conduct extensive experiments evaluating three benchmark datasets using several group fairness metrics and seven state-of-the-art LDP protocols. Overall, this study challenges the common belief that differential privacy necessarily leads to worsened fairness in machine learning.
On student-teacher deviations in distillation: does it pay to disobey?
Nagarajan, Vaishnavh, Menon, Aditya Krishna, Bhojanapalli, Srinadh, Mobahi, Hossein, Kumar, Sanjiv
Knowledge distillation (KD) has been widely-used to improve the test accuracy of a ``student'' network by training the student to mimic soft probabilities of a trained "teacher" network. Yet, it has been shown in recent work that, despite being trained to fit the teacher's probabilities, the student not only significantly deviates from these probabilities, but also performs even better than the teacher. Our work aims to reconcile this seemingly paradoxical observation by characterizing the precise nature of the student-teacher deviations, and by arguing how they can co-occur with better generalization. First, through experiments on image and language data, we identify that these deviations correspond to the student systematically exaggerating the confidence levels of the teacher. Next, we theoretically and empirically establish in some simple settings that KD also exaggerates the implicit bias of gradient descent in converging faster along the top eigendirections of the data. Finally, we demonstrate that this exaggerated bias effect can simultaneously result in both (a) the exaggeration of confidence and (b) the improved generalization of the student, thus offering a resolution to the apparent paradox. Our analysis brings existing theory and practice closer by considering the role of gradient descent in KD and by demonstrating the exaggerated bias effect in both theoretical and empirical settings.
Lifelong Reinforcement Learning with Modulating Masks
Ben-Iwhiwhu, Eseoghene, Nath, Saptarshi, Pilly, Praveen K., Kolouri, Soheil, Soltoggio, Andrea
Lifelong learning aims to create AI systems that continuously and incrementally learn during a lifetime, similar to biological learning. Attempts so far have met problems, including catastrophic forgetting, interference among tasks, and the inability to exploit previous knowledge. While considerable research has focused on learning multiple supervised classification tasks that involve changes in the input distribution, lifelong reinforcement learning (LRL) must deal with variations in the state and transition distributions, and in the reward functions. Modulating masks with a fixed backbone network, recently developed for classification, are particularly suitable to deal with such a large spectrum of task variations. In this paper, we adapted modulating masks to work with deep LRL, specifically PPO and IMPALA agents. The comparison with LRL baselines in both discrete and continuous RL tasks shows superior performance. We further investigated the use of a linear combination of previously learned masks to exploit previous knowledge when learning new tasks: not only is learning faster, the algorithm solves tasks that we could not otherwise solve from scratch due to extremely sparse rewards. The results suggest that RL with modulating masks is a promising approach to lifelong learning, to the composition of knowledge to learn increasingly complex tasks, and to knowledge reuse for efficient and faster learning.
ChatGPT better than undergraduates at solving SAT problems, study suggests
ChatGPT can solve problems at a level that matches or surpasses an undergraduate student, according to a new study. Researchers found that the GPT-3 large language model that underpins the chatbot performed about as well as US college undergraduates when asked to solve reasoning problems that appear on intelligence tests or exams such as the American college admission test, the SAT. Psychologists at the University of California, Los Angeles tested GPT-3's ability to predict the next image in a complex array of shapes, after converting the images to a text format that the model could process and also ensuring the model would never have encountered the questions before. The same problems were put to 40 UCLA undergraduates and the researchers found that GPT-3 solved 80% of the problems correctly, well above the average score of just below 60% for the human participants. The researchers also prompted the model to solve some SAT "analogy" questions โ selecting pairs of words that are linked in some way โ that they believe had not been published on the internet and therefore could not have appeared in the vast amount of data it was trained on.
ChatGPT sets its sights on university! AI bot can now reason as well as the average college student, study claims
Artificial intelligence can now reason as well as the average college student. Dr Geoffrey Hinton, who is seen as one of the godfathers of AI, warned recently that the technology'may soon be' more intelligent than people. Now it appears AI has mastered a type of intelligence called'analogical reasoning' which was previously believed to be uniquely human. Analogical reasoning means working out a solution to a completely new problem by using experience from previous similar problems. Given one type of test requiring this reasoning, the AI language programme GPT-3 beat the average score among 40 university students.
Unsupervised Improvement of Audio-Text Cross-Modal Representations
Wang, Zhepei, Subakan, Cem, Subramani, Krishna, Wu, Junkai, Tavares, Tiago, Ayres, Fabio, Smaragdis, Paris
Recent advances in using language models to obtain cross-modal audio-text representations have overcome the limitations of conventional training approaches that use predefined labels. This has allowed the community to make progress in tasks like zero-shot classification, which would otherwise not be possible. However, learning such representations requires a large amount of human-annotated audio-text pairs. In this paper, we study unsupervised approaches to improve the learning framework of such representations with unpaired text and audio. We explore domain-unspecific and domain-specific curation methods to create audio-text pairs that we use to further improve the model. We also show that when domain-specific curation is used in conjunction with a soft-labeled contrastive loss, we are able to obtain significant improvement in terms of zero-shot classification performance on downstream sound event classification or acoustic scene classification tasks.