Technology
Joint Morphological Generation and Syntactic Linearization
Song, Linfeng (Chinese Academy of Science) | Zhang, Yue (Singapore University of Technology and Design) | Song, Kai (Northeastern University) | Liu, Qun (Dublin City University and Chinese Academy of Science)
There has been growing interest in stochastic methods to natural language generation (NLG). While most NLG pipelines separate morphological generation and syntactic linearization, the two tasks are closely related. In this paper, we study joint morphological generation and linearization, making use of word order and inflections information for both tasks and reducing error propagation. Experiments show that the joint method significantly outperforms a strong pipelined baseline (by 1.1 BLEU points). It also achieves the best reported result on the Generation Challenge 2011 shared task.
Oversubscription Planning: Complexity and Compilability
Aghighi, Meysam (Linköping University) | Jonsson, Peter (Linköping University)
Many real-world planning problems are oversubscription problems where all goals are not simultaneously achievable and the planner needs to find a feasible subset. We present complexity results for the so-called partial satisfaction and net benefit problems under various restrictions; this extends previous work by van den Briel et al. Our results reveal strong connections between these problems and with classical planning. We also present a method for efficiently compiling oversubscription problems into the ordinary plan existence problem; this can be viewed as a continuation of earlier work by Keyder & Geffner.
Supervised Transfer Sparse Coding
Al-Shedivat, Maruan (King Abdullah University of Science and Technology) | Wang, Jim Jing-Yan (University at Buffalo, The State University of New York) | Alzahrani, Majed (King Abdullah University of Science and Technology) | Huang, Jianhua Z. (Texas A&M University) | Gao, Xin (King Abdullah University of Science and Technology)
A combination of the sparse coding and transfer learning techniques was shown to be accurate and robust in classification tasks where training and testing objects have a shared feature space but are sampled from different underlying distributions, i.e., belong to different domains. The key assumption in such case is that in spite of the domain disparity, samples from different domains share some common hidden factors. Previous methods often assumed that all the objects in the target domain are unlabeled, and thus the training set solely comprised objects from the source domain. However, in real world applications, the target domain often has some labeled objects, or one can always manually label a small number of them. In this paper, we explore such possibility and show how a small number of labeled data in the target domain can significantly leverage classification accuracy of the state-of-the-art transfer sparse coding methods. We further propose a unified framework named supervised transfer sparse coding (STSC) which simultaneously optimizes sparse representation, domain transfer and classification. Experimental results on three applications demonstrate that a little manual labeling and then learning the model in a supervised fashion can significantly improve classification accuracy.
Labeling Complicated Objects: Multi-View Multi-Instance Multi-Label Learning
Nguyen, Cam-Tu (Nanjing University) | Wang, Xiaoliang (Nanjing University) | Liu, Jing (Institute of Automation Chinese Academy of Sciences) | Zhou, Zhi-Hua (Nanjing University)
Multi-Instance Multi-Label (MIML) is a learning framework where an example is associated with multiple labels and represented by a set of feature vectors (multiple instances). In the formalization of MIML learning, instances come from a single source (single view). To leverage multiple information sources (multi-view), we develop a multi-view MIML framework based on hierarchical Bayesian Network, and derive an effective learning algorithm based on variational inference. The model can naturally deal with examples in which some views could be absent (partial examples). On multi-view datasets, it is shown that our method is better than other multi-view and single-view approaches particularly in the presence of partial examples. On single-view benchmarks, extensive evaluation shows that our method is highly competitive or better than other MIML approaches on labeling examples and instances. Moreover, our method can effectively handle datasets with a large number of labels.
Robust Non-Negative Dictionary Learning
Pan, Qihe (Beihang University) | Kong, Deguang (University of Texas Arlington) | Ding, Chris (University of Texas Arlington) | Luo, Bin (Anhui University)
Dictionary learning plays an important role in machine learning, where data vectors are modeled as a sparse linear combinations of basis factors (i.e., dictionary). However, how to conduct dictionary learning in noisy environment has not been well studied. Moreover, in practice, the dictionary (i.e., the lower rank approximation of the data matrix) and the sparse representations are required to be nonnegative, such as applications for image annotation, document summarization, microarray analysis. In this paper, we propose a new formulation for non-negative dictionary learning in noisy environment, where structure sparsity is enforced on sparse representation. The proposed new formulation is also robust for data with noises and outliers, due to a robust loss function used. We derive an efficient multiplicative updating algorithm to solve the optimization problem, where dictionary and sparse representation are updated iteratively. We prove the convergence and correctness of proposed algorithm rigorously.We show the differences of dictionary at different level of sparsity constraint.The proposed algorithm can be adapted for clustering and semi-supervised learning.
Cost-Based Query Optimization via AI Planning
Robinson, Nathan (Australian National University) | McIlraith, Sheila (University of Toronto) | Toman, David (University of Waterloo)
In this paper we revisit the problem of generating query plans using AI automated planning with a view to leveraging significant recent advances in state-of-the-art planning techniques. Our efforts focus on the specific problem of cost-based join-order optimization for conjunctive relational queries, a critical component of production-quality query optimizers. We characterize the general query-planning problem as a delete-free planning problem, and query plan optimization as a context-sensitive cost-optimal planning problem. We propose algorithms that generate high-quality query plans, guaranteeing optimality under certain conditions. Our approach is general, supporting the use of a broad suite of domain-independent and domain-specific optimization criteria. Experimental results demonstrate the effectiveness of AI planning techniques for query plan generation and optimization.
Semantic Segmentation Using Multiple Graphs with Block-Diagonal Constraints
Zhang, Ke (Fudan University) | Zhang, Wei (Fudan University) | Zeng, Sheng (Fudan University) | Xue, Xiangyang (Fudan University)
In this paper we propose a novel method for image semantic segmentation using multiple graphs. The multiview affinity graph is constructed by leveraging the consistency between semantic space and multiple visualspaces. With block-diagonal constraints, we enforce the affinity matrix to be sparse such that the pairwise potential for dissimilar superpixels is close to zero. By a divide-and-conquer strategy, the optimizationfor learning affinity matrix is decomposed into several subproblems that can be solved in parallel. Using the neighborhood relationship between superpixels and the consistency between affinity matrix and labelconfidencematrix, we infer the semantic label for each superpixel of unlabeled images by minimizing an objective whose closed form solution can be easily obtained. Experimental results on two real-world image datasetsdemonstrate the effectiveness of our method.
A Support-Based Algorithm for the Bi-Objective Pareto Constraint
Hartert, Renaud (UCLouvain) | Schaus, Pierre (UCLouvain)
Bi-Objective Combinatorial Optimization problems are ubiquitous in real-world applications and designing approaches to solve them efficiently is an important research area of Artificial Intelligence. In Constraint Programming, the recently introduced bi-objective Pareto constraint allows one to solve bi-objective combinatorial optimization problems exactly. Using this constraint, every non-dominated solution is collected in a single tree-search while pruning sub-trees that cannot lead to a non-dominated solution. This paper introduces a simpler and more efficient filtering algorithm for the bi-objective Pareto constraint. The efficiency of this algorithm is experimentally confirmed on classical bi-objective benchmarks.
Scheduling for Transfers in Pickup and Delivery Problems with Very Large Neighborhood Search
Coltin, Brian (The Robotics Institute, Carnegie Mellon University) | Veloso, Manuela (Carnegie Mellon University)
In pickup and delivery problems (PDPs), vehicles pickup and deliver a set of items under various constraints. We address the PDP with Transfers (PDP-T), in which vehicles plan to transfer items between one another to form more efficient schedules. We introduce the Very Large Neighborhood Search with Transfers (VLNS-T) algorithm to form schedules for the PDP-T. Our approach allows multiple transfers for items at arbitrary locations, and is not restricted to a set of predefined transfer points. We show that VLNS-T improves upon the best known PDP solutions for benchmark problems, and demonstrate its effectiveness on problems sampled from real world taxi data in New York City.