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Deterministic Bounds and Random Estimates of Metric Tensors on Neuromanifolds

arXiv.org Machine Learning

The high dimensional parameter space of modern deep neural networks -- the neuromanifold -- is endowed with a unique metric tensor defined by the Fisher information, estimating which is crucial for both theory and practical methods in deep learning. To analyze this tensor for classification networks, we return to a low dimensional space of probability distributions -- the core space -- and carefully analyze the spectrum of its Riemannian metric. We extend our discoveries there into deterministic bounds of the metric tensor on the neuromanifold. We introduce an unbiased random estimate of the metric tensor and its bounds based on Hutchinson's trace estimator. It can be evaluated efficiently through a single backward pass and can be used to estimate the diagonal, or block diagonal, or the full tensor. Its quality is guaranteed with a standard deviation bounded by the true value up to scaling.


A system identification approach to clustering vector autoregressive time series

arXiv.org Machine Learning

Clustering of time series based on their underlying dynamics is keeping attracting researchers due to its impacts on assisting complex system modelling. Most current time series clustering methods handle only scalar time series, treat them as white noise, or rely on domain knowledge for high-quality feature construction, where the autocorrelation pattern/feature is mostly ignored. Instead of relying on heuristic feature/metric construction, the system identification approach allows treating vector time series clustering by explicitly considering their underlying autoregressive dynamics. We first derive a clustering algorithm based on a mixture autoregressive model. Unfortunately it turns out to have significant computational problems. We then derive a `small-noise' limiting version of the algorithm, which we call k-LMVAR (Limiting Mixture Vector AutoRegression), that is computationally manageable. We develop an associated BIC criterion for choosing the number of clusters and model order. The algorithm performs very well in comparative simulations and also scales well computationally.


$α$-GAN by Rényi Cross Entropy

arXiv.org Artificial Intelligence

This paper proposes $α$-GAN, a generative adversarial network using Rényi measures. The value function is formulated, by Rényi cross entropy, as an expected certainty measure incurred by the discriminator's soft decision as to where the sample is from, true population or the generator. The discriminator tries to maximize the Rényi certainty about sample source, while the generator wants to reduce it by injecting fake samples. This forms a min-max problem with the solution parameterized by the Rényi order $α$. This $α$-GAN reduces to vanilla GAN at $α= 1$, where the value function is exactly the binary cross entropy. The optimization of $α$-GAN is over probability (vector) space. It is shown that the gradient is exponentially enlarged when Rényi order is in the range $α\in (0,1)$. This makes convergence faster, which is verified by experimental results. A discussion shows that choosing $α\in (0,1)$ may be able to solve some common problems, e.g., vanishing gradient. A following observation reveals that this range has not been fully explored in the existing Rényi version GANs.


EmoMeta: A Multimodal Dataset for Fine-grained Emotion Classification in Chinese Metaphors

arXiv.org Artificial Intelligence

Metaphors play a pivotal role in expressing emotions, making them crucial for emotional intelligence. The advent of multimodal data and widespread communication has led to a proliferation of multimodal metaphors, amplifying the complexity of emotion classification compared to single-mode scenarios. However, the scarcity of research on constructing multimodal metaphorical fine-grained emotion datasets hampers progress in this domain. Moreover, existing studies predominantly focus on English, overlooking potential variations in emotional nuances across languages. To address these gaps, we introduce a multimodal dataset in Chinese comprising 5,000 text-image pairs of metaphorical advertisements. Each entry is meticulously annotated for metaphor occurrence, domain relations and fine-grained emotion classification encompassing joy, love, trust, fear, sadness, disgust, anger, surprise, anticipation, and neutral. Our dataset is publicly accessible (https://github.com/DUTIR-YSQ/EmoMeta), facilitating further advancements in this burgeoning field.


Learning Probabilistic Temporal Logic Specifications for Stochastic Systems

arXiv.org Artificial Intelligence

There has been substantial progress in the inference of formal behavioural specifications from sample trajectories, for example using Linear Temporal Logic (L TL). However, these techniques cannot handle specifications that correctly characterise systems with stochastic behaviour, which occur commonly in reinforcement learning and formal verification. We consider the passive learning problem of inferring a Boolean combination of probabilistic L TL (PL TL) formulas from a set of Markov chains, classified as either positive or negative. We propose a novel learning algorithm that infers concise PL TL specifications, leveraging grammar-based enumeration, search heuristics, probabilistic model checking and Boolean set-cover procedures. We demonstrate the effectiveness of our algorithm in two use cases: learning from policies induced by RL algorithms and learning from variants of a probabilistic model. In both cases, our method automatically and efficiently extracts PL TL specifications that succinctly characterize the temporal differences between the policies or model variants.


PoLO: Proof-of-Learning and Proof-of-Ownership at Once with Chained Watermarking

arXiv.org Artificial Intelligence

Machine learning models are increasingly shared and outsourced, raising requirements of verifying training effort (Proof-of-Learning, PoL) to ensure claimed performance and establishing ownership (Proof-of-Ownership, PoO) for transactions. When models are trained by untrusted parties, PoL and PoO must be enforced together to enable protection, attribution, and compensation. However, existing studies typically address them separately, which not only weakens protection against forgery and privacy breaches but also leads to high verification overhead. We propose PoLO, a unified framework that simultaneously achieves PoL and PoO using chained watermarks. PoLO splits the training process into fine-grained training shards and embeds a dedicated watermark in each shard. Each watermark is generated using the hash of the preceding shard, certifying the training process of the preceding shard. The chained structure makes it computationally difficult to forge any individual part of the whole training process. The complete set of watermarks serves as the PoL, while the final watermark provides the PoO. PoLO offers more efficient and privacy-preserving verification compared to the vanilla PoL solutions that rely on gradient-based trajectory tracing and inadvertently expose training data during verification, while maintaining the same level of ownership assurance of watermark-based PoO schemes. Our evaluation shows that PoLO achieves 99% watermark detection accuracy for ownership verification, while preserving data privacy and cutting verification costs to just 1.5-10% of traditional methods. Forging PoLO demands 1.1-4x more resources than honest proof generation, with the original proof retaining over 90% detection accuracy even after attacks.


ToLeaP: Rethinking Development of Tool Learning with Large Language Models

arXiv.org Artificial Intelligence

Tool learning, which enables large language models (LLMs) to utilize external tools effectively, has garnered increasing attention for its potential to revolutionize productivity across industries. Despite rapid development in tool learning, key challenges and opportunities remain understudied, limiting deeper insights and future advancements. In this paper, we investigate the tool learning ability of 41 prevalent LLMs by reproducing 33 benchmarks and enabling one-click evaluation for seven of them, forming a Tool Learning Platform named ToLeaP. We also collect 21 out of 33 potential training datasets to facilitate future exploration. After analyzing over 3,000 bad cases of 41 LLMs based on ToLeaP, we identify four main critical challenges: (1) benchmark limitations induce both the neglect and lack of (2) autonomous learning, (3) generalization, and (4) long-horizon task-solving capabilities of LLMs. To aid future advancements, we take a step further toward exploring potential directions, namely (1) real-world benchmark construction, (2) compatibility-aware autonomous learning, (3) rationale learning by thinking, and (4) identifying and recalling key clues. The preliminary experiments demonstrate their effectiveness, highlighting the need for further research and exploration.


Communication-Efficient Hybrid Language Model via Uncertainty-Aware Opportunistic and Compressed Transmission

arXiv.org Artificial Intelligence

--T o support emerging language-based applications using dispersed and heterogeneous computing resources, the hybrid language model (HLM) offers a promising architecture, where an on-device small language model (SLM) generates draft tokens that are validated and corrected by a remote large language model (LLM). However, the original HLM suffers from substantial communication overhead, as the LLM requires the SLM to upload the full vocabulary distribution for each token. Moreover, both communication and computation resources are wasted when the LLM validates tokens that are highly likely to be accepted. T o overcome these limitations, we propose communication-efficient and uncertainty-aware HLM (CU-HLM) . In CU-HLM, the SLM transmits truncated vocabulary distributions only when its output uncertainty is high. Furthermore, we theoretically derive optimal uncertainty thresholds and optimal vocabulary truncation strategies. Simulation results show that, compared to standard HLM, CU-HLM achieves up to 206 higher token throughput by skipping 74.8% transmissions with 97.4% vocabulary compression, while maintaining 97.4% accuracy. ARGE language models (LLMs), with their massive parameter counts and rich training data, have demonstrated remarkable emergent capabilities [1]. These capabilities span a wide range of applications, including open-domain question answering, code generation, commonsense reasoning, and even robotic control [2]-[6]. To seamlessly adopt LLMs into a wireless edge environment, the hybrid language model (HLM) framework [7] has emerged, which physically splits the inference task between an on-device small language model (SLM) and a remote LLM.


Unsupervised Port Berth Identification from Automatic Identification System Data

arXiv.org Artificial Intelligence

Port berthing sites are regions of high interest for monitoring and optimizing port operations. Data sourced from the Automatic Identification System (AIS) can be superimposed on berths enabling their real-time monitoring and revealing long-term utilization patterns. Ultimately, insights from multiple berths can uncover bottlenecks, and lead to the optimization of the underlying supply chain of the port and beyond. However, publicly available documentation of port berths, even when available, is frequently incomplete - e.g. there may be missing berths or inaccuracies such as incorrect boundary boxes - necessitating a more robust, data-driven approach to port berth localization. In this context, we propose an unsupervised spatial modeling method that leverages AIS data clustering and hyperparameter optimization to identify berthing sites. Trained on one month of freely available AIS data and evaluated across ports of varying sizes, our models significantly outperform competing methods, achieving a mean Bhattacharyya distance of 0.85 when comparing Gaussian Mixture Models (GMMs) trained on separate data splits, compared to 13.56 for the best existing method. Qualitative comparison with satellite images and existing berth labels further supports the superiority of our method, revealing more precise berth boundaries and improved spatial resolution across diverse port environments.


Zero-Shot Visual Generalization in Robot Manipulation

arXiv.org Artificial Intelligence

A key requirement of any generalist robot system deployed in the real-world is the ability to perform tasks across visually diverse environments. High-dimensional inputs like RGB images offer rich information but also introduce complexity due to the curse of dimensionality. Given the enormous diversity of real-world visual data, accounting for every possible variation within a fixed dataset is intractable. Extracting the underlying structural knowledge of the world from visual data while being robust to semantically irrelevant visual perturbations remains an open question. The robot learning field has largely relied on one of several trends, one of which is to train agents in simulation, where visual complexity can be controlled and large-scale synthetic and diverse data can be generated efficiently through GPU-accelerated simulators [1, 2, 3]. However, transferring policies trained in simulation to the real world is hindered by the "Sim2Real" gap caused by mismatches in fidelity and unmodeled dynamics. Domain randomization is the leading strategy to close this gap by varying the simulation parameters such that real-world conditions fall within the distribution of the training data. Domain randomization has proven effective in both simulated benchmarks and real-world robotic tasks when the data diversity is sufficiently large [4, 5, 6]. A seemingly unrelated but conceptually similar approach to visual generalization in the age of foundation models has been to train large Figure 1: Behavior cloning with disentangled representations and associative latent dynamics achieves zero-shot generalization to various real world perturbations, such as changes in ambient lighting ( left), object color ( middle-left), directed lighting ( middle-right), and the presence of dis-tractor objects ( right).