Goto

Collaborating Authors

 distance-based method


Feature Bank Enhancement for Distance-based Out-of-Distribution Detection

Liu, Yuhang, Wu, Yuefei, Shi, Bin, Dong, Bo

arXiv.org Artificial Intelligence

Out-of-distribution (OOD) detection is critical to ensuring the reliability of deep learning applications and has attracted significant attention in recent years. A rich body of literature has emerged to develop efficient score functions that assign high scores to in-distribution (ID) samples and low scores to OOD samples, thereby helping distinguish OOD samples. Among these methods, distance-based score functions are widely used because of their efficiency and ease of use. However, deep learning often leads to a biased distribution of data features, and extreme features are inevitable. These extreme features make the distance-based methods tend to assign too low scores to ID samples. This limits the OOD detection capabilities of such methods. To address this issue, we propose a simple yet effective method, Feature Bank Enhancement (FBE), that uses statistical characteristics from dataset to identify and constrain extreme features to the separation boundaries, therapy making the distance between samples inside and outside the distribution farther. We conducted experiments on large-scale ImageNet-1k and CIFAR-10 respectively, and the results show that our method achieves state-of-the-art performance on both benchmark. Additionally, theoretical analysis and supplementary experiments are conducted to provide more insights into our method.


Speech Foundation Models and Crowdsourcing for Efficient, High-Quality Data Collection

Lee, Beomseok, Gaido, Marco, Calapodescu, Ioan, Besacier, Laurent, Negri, Matteo

arXiv.org Artificial Intelligence

As in any data-intensive domain, collecting highquality To fill this gap, this paper explores the use datasets is a fundamental and costly prerequisite of SFMs to automatize the validation of crowdsourced for the development of speech-processing speech data. To this aim, we investigate the applications. Traditional methods heavily rely on employment of off-the-shelf SFMs such as Whisper human workforce, whose costs, as data collection and SeamlessM4T (Radford et al., 2022; Communication scales, are hard to sustain. In the quest for scalable et al., 2023), along with machine translation solutions to tackle this problem, crowdsourcing (MT) models and grapheme-to-phoneme conversion emerged as a viable option that also enables the coverage (G2P). Through experiments on French, of diverse populations (Cefkin et al., 2014; German, and Korean data, we test the integration Poesio et al., 2017). Due to the variable quality of of SFMs and crowdsourcing to reduce validation crowd-sourced data, validation methods that discard costs while preserving final data quality. Our results low-quality contributions are essential to build show that leveraging SFMs yields a cost reduction reliable datasets (Negri et al., 2011; Sabou et al., by over 40%, while maintaining high data quality, 2014; Chittilappilly et al., 2016). This need is exacerbated significantly improving the efficiency and scalability in the collection of speech-text pairs, where of crowd-sourced speech data collection.


GLIMMER: Incorporating Graph and Lexical Features in Unsupervised Multi-Document Summarization

Liu, Ran, Liu, Ming, Yu, Min, Jiang, Jianguo, Li, Gang, Zhang, Dan, Li, Jingyuan, Meng, Xiang, Huang, Weiqing

arXiv.org Artificial Intelligence

Pre-trained language models are increasingly being used in multi-document summarization tasks. However, these models need large-scale corpora for pre-training and are domain-dependent. Other non-neural unsupervised summarization approaches mostly rely on key sentence extraction, which can lead to information loss. To address these challenges, we propose a lightweight yet effective unsupervised approach called GLIMMER: a Graph and LexIcal features based unsupervised Multi-docuMEnt summaRization approach. It first constructs a sentence graph from the source documents, then automatically identifies semantic clusters by mining low-level features from raw texts, thereby improving intra-cluster correlation and the fluency of generated sentences. Finally, it summarizes clusters into natural sentences. Experiments conducted on Multi-News, Multi-XScience and DUC-2004 demonstrate that our approach outperforms existing unsupervised approaches. Furthermore, it surpasses state-of-the-art pre-trained multi-document summarization models (e.g. PEGASUS and PRIMERA) under zero-shot settings in terms of ROUGE scores. Additionally, human evaluations indicate that summaries generated by GLIMMER achieve high readability and informativeness scores. Our code is available at https://github.com/Oswald1997/GLIMMER.


Propagative Distance Optimization for Constrained Inverse Kinematics

Chen, Yu, Cai, Yilin, Xu, Jinyun, Ren, Zhongqiang, Shi, Guanya, Choset, Howie

arXiv.org Artificial Intelligence

This paper investigates a constrained inverse kinematic (IK) problem that seeks a feasible configuration of an articulated robot under various constraints such as joint limits and obstacle collision avoidance. Due to the high-dimensionality and complex constraints, this problem is often solved numerically via iterative local optimization. Classic local optimization methods take joint angles as the decision variable, which suffers from non-linearity caused by the trigonometric constraints. Recently, distance-based IK methods have been developed as an alternative approach that formulates IK as an optimization over the distances among points attached to the robot and the obstacles. Although distance-based methods have demonstrated unique advantages, they still suffer from low computational efficiency, since these approaches usually ignore the chain structure in the kinematics of serial robots. This paper proposes a new method called propagative distance optimization for constrained inverse kinematics (PDO-IK), which captures and leverages the chain structure in the distance-based formulation and expedites the optimization by computing forward kinematics and the Jacobian propagatively along the kinematic chain. Test results show that PDO-IK runs up to two orders of magnitude faster than the existing distance-based methods under joint limits constraints and obstacle avoidance constraints. It also achieves up to three times higher success rates than the conventional joint-angle-based optimization methods for IK problems. The high runtime efficiency of PDO-IK allows the real-time computation (10$-$1500 Hz) and enables a simulated humanoid robot with 19 degrees of freedom (DoFs) to avoid moving obstacles, which is otherwise hard to achieve with the baselines.


Distributed end-effector formation control for mixed fully- and under-actuated manipulators with flexible joints

Peng, Zhiyu, Jayawardhana, Bayu, Xin, Xin

arXiv.org Artificial Intelligence

The presence of faulty or underactuated manipulators can disrupt the end-effector formation keeping of a team of manipulators. Based on two-link planar manipulators, we investigate this end-effector formation keeping problem for mixed fully- and under-actuated manipulators with flexible joints. In this case, the underactuated manipulators can comprise of active-passive (AP) manipulators, passive-active (PA) manipulators, or a combination thereof. We propose distributed control laws for the different types of manipulators to achieve and maintain the desired formation shape of the end-effectors. It is achieved by assigning virtual springs to the end-effectors for the fully-actuated ones and to the virtual end-effectors for the under-actuated ones. We study further the set of all desired and reachable shapes for the networked manipulators' end-effectors. Finally, we validate our analysis via numerical simulations.


Estimating the Number of Clusters via Normalized Cluster Instability

Haslbeck, Jonas M. B., Wulff, Dirk U.

arXiv.org Machine Learning

We improve existing instability-based methods for the selection of the number of clusters $k$ in cluster analysis by normalizing instability. In contrast to existing instability methods which only perform well for bounded sequences of small $k$, our method performs well across the whole sequence of possible $k$. In addition, we compare for the first time model-based and model-free variants of $k$ selection via cluster instability and find that their performance is similar. We make our method available in the R-package \verb+cstab+.