Technology
OMNI-Prop: Seamless Node Classification on Arbitrary Label Correlation
Yamaguchi, Yuto (University of Tsukuba) | Faloutsos, Christos (Carnegie Mellon University) | Kitagawa, Hiroyuki (University of Tsukuba)
If we know most of Smithโs friends are from Boston, what can we say about the rest of Smithโs friends? In this paper, we focus on the node classification problem on networks, which is one of the most important topics in AI and Web communities. Our proposed algorithm which is referred to as OMNIProp has the following properties: (a) seamless and accurate; it works well on any label correlations (i.e., homophily, heterophily, and mixture of them) (b) fast; it is efficient and guaranteed to converge on arbitrary graphs (c) quasi-parameter free; it has just one well-interpretable parameter with heuristic default value of 1. We also prove the theoretical connections of our algorithm to the semi-supervised learning (SSL) algorithms and to random-walks. Experiments on four real, different network datasets demonstrate the benefits of the proposed algorithm, where OMNI-Prop outperforms the top competitors.
A Bayesian Approach to Perceptual 3D Object-Part Decomposition Using Skeleton-Based Representations
El-Gaaly, Tarek (Rutgers University) | Froyen, Vicky (Rutgers University) | Elgammal, Ahmed (Rutgers University) | Feldman, Jacob (Rutgers University) | Singh, Manish (Rutgers University)
We present a probabilistic approach to shape decomposition that creates a skeleton-based shape representation of a 3D object while simultaneously decomposing it into constituent parts. Our approach probabilistically combines two prominent threads from the shape literature: skeleton-based (medial axis) representations of shape, and part-based representations of shape, in which shapes are combinations of primitive parts. Our approach recasts skeleton-based shape representation as a mixture estimation problem, allowing us to apply probabilistic estimation techniques to the problem of 3D shape decomposition, extending earlier work on the 2D case. The estimated 3D shape decompositions approximate human shape decomposition judgments. We present a tractable implementation of the framework, which begins by over-segmenting objects at concavities, and then probabilistically merges them to create a distribution over possible decompositions. This results in a hierarchy of decompositions at different structural scales, again closely matching known properties of human shape representation. The probabilistic estimation procedures that arise naturally in the model allow effective prediction of missing parts. We present results on shapes from a standard database illustrating the effectiveness of the approach.
Improving Exploration in UCT Using Local Manifolds
Srinivasan, Sriram (University of Alberta) | Talvitie, Erik (Franklin and Marshal College) | Bowling, Michael (University of Alberta)
Monte-Carlo planning has been proven successful in manysequential decision-making settings, but it suffers from poorexploration when the rewards are sparse. In this paper, weimprove exploration in UCT by generalizing across similarstates using a given distance metric. We show that this algorithm,like UCT, converges asymptotically to the optimalaction. When the state space does not have a natural distancemetric, we show how we can learn a local manifold from thetransition graph of states in the near future. to obtain a distancemetric. On domains inspired by video games, empiricalevidence shows that our algorithm is more sample efficientthan UCT, particularly when rewards are sparse.
A Comparison of Qualitative and Metric Spatial Relation Models for Scene Understanding
Thippur, Akshaya (KTH Royal Institute of Technology) | Burbridge, Chris (University of Birmingham) | Kunze, Lars (University of Birmingham) | Alberti, Marina (KTH Royal Institute of Technology) | Folkesson, John (KTH Royal Institute of Technology) | Jensfelt, Patric (KTH Royal Institute of Technology) | Hawes, Nick (University of Birmingham)
Object recognition systems can be unreliable when run in isolation depending on only image based features, but their performance can be improved when taking scene context into account. In this paper, we present techniques to model and infer object labels in real scenes based on a variety of spatial relations โ geometric features which capture how objects co-occur โ and compare their efficacy in the context of augmenting perception based object classification in real-world table-top scenes. We utilise a long-term dataset of office table-tops for qualitatively comparing the performances of these techniques. On this dataset, we show that more intricate techniques, have a superior performance but do not generalise well on small training data. We also show that techniques using coarser information perform crudely but sufficiently well in standalone scenarios and generalise well on small training data. We conclude the paper, expanding on the insights we have gained through these comparisons and comment on a few fundamental topics with respect to long-term autonomous robots.
Unsupervised Phrasal Near-Synonym Generation from Text Corpora
Gupta, Dishan (Carnegie Mellon University) | Carbonell, Jaime (Carnegie Mellon University) | Gershman, Anatole (Carnegie Mellon University) | Klein, Steve (Meaningful Machines, LLC) | Miller, David (Meaningful Machines, LLC)
Unsupervised discovery of synonymous phrases is useful in a variety of tasks ranging from text mining and search engines to semantic analysis and machine translation. This paper presents an unsupervised corpus-based conditional model: Near-Synonym System (NeSS) for finding phrasal synonyms and near synonyms that requires only a large monolingual corpus. The method is based on maximizing information-theoretic combinations of shared contexts and is parallelizable for large-scale processing. An evaluation framework with crowd-sourced judgments is proposed and results are compared with alternate methods, demonstrating considerably superior results to the literature and to thesaurus look up for multi-word phrases. Moreover, the results show that the statistical scoring functions and overall scalability of the system are more important than language specific NLP tools. The method is language-independent and practically useable due to accuracy and real-time performance via parallel decomposition.
asprin: Customizing Answer Set Preferences without a Headache
Brewka, Gerhard (University of Leipzig) | Delgrande, James (Simon Fraser University) | Romero, Javier (University of Potsdam) | Schaub, Torsten (University of Potsdam)
In this paper we describe asprin, a general, flexible, and extensible framework for handling preferences among the stable models of a logic program. We show how complex preference relations can be specified through user-defined preference types and their arguments. We describe how preference specifications are handled internally by so-called preference programs, which are used for dominance testing. We also give algorithms for computing one, or all, optimal stable models of a logic program. Notably, our algorithms depend on the complexity of the dominance tests and make use of multi-shot answer set solving technology.
World WordNet Database Structure: An Efficient Schema for Storing Information of WordNets of the World
Redkar, Hanumant Harichandra (Indian Institute of Technology Bombay) | Bhingardive, Sudha Baban (Indian Institute of Technology Bombay) | Kanojia, Diptesh (Indian Institute of Technology Bombay) | Bhattacharyya, Pushpak (Indian Institute of Technology Bombay)
WordNet is an online lexical resource which expresses unique concepts in a language. English WordNet is the first WordNet which was developed at Princeton University. Over a period of time, many language WordNets were developed by various organizations all over the world. It has always been a challenge to store the WordNet data. Some WordNets are stored using file system and some WordNets are stored using different database models. In this paper, we present the World WordNet Database Structure which can be used to efficiently store the WordNet information of all languages of the World. This design can be adapted by most language WordNets to store information such as synset data, semantic and lexical relations, ontology details, language specific features, linguistic information, etc. An attempt is made to develop Application Programming Interfaces to manipulate the data from these databases. This database structure can help in various Natural Language Processing applications like Multilingual Information Retrieval, Word Sense Disambiguation, Machine Translation, etc.
Learning Word Vectors Efficiently Using Shared Representations and Document Representations
Luo, Qun (Beijing University of Posts and Telecommunications) | Xu, Weiran (Beijing University of Posts and Telecommunications)
We propose some better word embedding models based on vLBL model and ivLBL model by sharing representations between context and target words and using document representations. Our proposed models are much simpler which have almost half less parameters than the state-of-the-art methods. We achieve better results on word analogy task than the best ones reported before using significantly less training data and computing time.
A Nonconvex Relaxation Approach for Rank Minimization Problems
Zhong, Xiaowei (University of Science and Technology of China) | Xu, Linli (University of Science and Technology of China) | Li, Yitan (University of Science and Technology of China) | Liu, Zhiyuan (University of Science and Technology of China) | Chen, Enhong (University of Science and Technology of China)
Recently, solving rank minimization problems by leveraging nonconvex relaxations has received significant attention. Some theoretical analyses demonstrate that it can provide a better approximation of original problems than convex relaxations. However, designing an effective algorithm to solve nonconvex optimization problems remains a big challenge. In this paper, we propose an Iterative Shrinkage-Thresholding and Reweighted Algorithm (ISTRA) to solve rank minimization problems using the nonconvex weighted nuclear norm as a low rank regularizer. We prove theoretically that under certain assumptions our method achieves a high-quality local optimal solution efficiently. Experimental results on synthetic and real data show that the proposed ISTRA algorithm outperforms state-of-the-art methods in both accuracy and efficiency.
Improving Cross-Domain Recommendation through Probabilistic Cluster-Level Latent Factor Model
Ren, Siting (Beijing University of Posts and Telecommunications) | Gao, Sheng (PRIS - Beijing University of Posts and Telecommunications) | Liao, Jianxin (Beijing University of Posts and Telecommunications) | Guo, Jun (PRIS - Beijing University of Posts and Telecommunications)
Cross-domain recommendation has been proposed to transfer user behavior pattern by pooling together the rating data from multiple domains to alleviate the sparsity problem appearing in single rating domains. However, previous models only assume that multiple domains share a latent common rating pattern based on the user-item co-clustering. To capture diversities among different domains, we propose a novel Probabilistic Cluster-level Latent Factor (PCLF) model to improve the cross-domain recommendation performance. Experiments on several real world datasets demonstrate that our proposed model outperforms the state-of-the-art methods for the cross-domain recommendation task.