A significant challenge to make learning techniques more suitable for general purpose use is to move beyond i) complete supervision, ii) low dimensional data, iii) a single task and single view per instance. Solving these challenges allows working with "Big Data" problems that are typically high dimensional with multiple (but possibly incomplete) labelings and views. While other work has addressed each of these problems separately, in this paper we show how to address them together, namely semi-supervised dimension reduction for multi-task and multi-view learning (SSDR-MML), which performs optimization for dimension reduction and label inference in semi-supervised setting. The proposed framework is designed to handle both multi-task and multi-view learning settings, and can be easily adapted to many useful applications. Information obtained from all tasks and views is combined via reconstruction errors in a linear fashion that can be efficiently solved using an alternating optimization scheme. Our formulation has a number of advantages. We explicitly model the information combining mechanism as a data structure (a weight nearest-neighbor matrix) which allows investigating fundamental questions in multi-task and multi-view learning. We address one such question by presenting a general measure to quantify the success of simultaneous learning of multiple tasks or from multiple views. We show that our SSDR-MML approach can outperform many state-of-the-art baseline methods and demonstrate the effectiveness of connecting dimension reduction and learning.
Various dimension reduction methods have been proposed to simplify learning problems, which generally fall into three categories: unsupervised, supervised, and semi-supervised. In contrast to traditional classification tasks where classes are mutually exclusive, the classes in multi-task label learning are actually overlapped and correlated. Thus, two specialized multi-task dimension reduction algorithms have been proposed in @cite_17 and @cite_6 , both of which try to capture the correlations between multiple tasks. However, the usefulness of such methods is dramatically limited by requiring complete label knowledge, which is very expensive to obtain and even impossible for those extremely large dataset, e.g. web images annotation. In order to utilize unlabeled data, there are many semi-supervised multi-label learning algorithms have been proposed @cite_7 @cite_3 , which solve learning problem by optimizing the objective function over graph or hypergraph. However, the performance of such approach is weakened by the lack of the concatenation of dimension reduction and learning algorithm. To the best of our knowledge, @cite_10 is the first attempt to connect dimension reduction and multi-task label learning, but it suffers from the inability of utilizing unlabeled data.
@cite_7 @cite_3 @cite_6 @cite_10 @cite_17
1513235864 2584571478 1979899483 2056974656
A significant challenge to make learning techniques more suitable for general purpose use in AI is to move beyond i) complete supervision, ii) low dimensional data and iii) a single label per instance. Solving this challenge would allow making predictions for high dimensional large dataset with multiple (but possibly incomplete) labelings. While other work has addressed each of these problems separately, in this paper we show how to address them together, namely the problem of semi-supervised dimension reduction for multi-labeled classification, SSDR-MC. To our knowledge this is the first paper that attempts to address all challenges together. In this work, we study a novel joint learning framework which performs optimization for dimension reduction and multi-label inference in semi-supervised setting. The experimental results validate the performance of our approach, and demonstrate the effectiveness of connecting dimension reduction and learning. Multi-label data with high dimensionality arise frequently in data mining and machine learning. It is not only time consuming but also computationally unreliable when we use high-dimensional data directly. Supervised dimensionality reduction approaches are based on the assumption that there are large amounts of labeled data. It is infeasible to label a large number of training samples in practice especially in multi-label learning. To address these challenges, we propose a novel algorithm, namely Semi-Supervised Multi-Label Dimensionality Reduction (SSMLDR), which can utilize the information from both labeled data and unlabeled data in an effective way. First, the proposed algorithm enlarges the multi-label information from the labeled data to the unlabeled data through a special designed label propagation method. It then learns a transformation matrix to perform dimensionality reduction by incorporating the enlarged multi-label information. Extensive experiments on a broad range of datasets validate the effectiveness of our approach against other well-established algorithms. Multi-label data with high dimensionality often occurs, which will produce large time and energy overheads when directly used in classification tasks. To solve this problem, a novel algorithm called multi-label dimensionality reduction via semi-supervised discriminant analysis (MSDA) was proposed. It was expected to derive an objective discriminant function as smooth as possible on the data manifold by multi-label learning and semi-supervised learning. By virtue of the latent imformation, which was provided by the graph weighted matrix of sample attributes and the similarity correlation matrix of partial sample labels, MSDA readily made the separability between different classes achieve maximization and estimated the intrinsic geometric structure in the lower manifold space by employing unlabeled data. Extensive experimental results on several real multi-label datasets show that after dimensionality reduction using MSDA, the average classification accuracy is about 9.71 higher than that of other algorithms, and several evaluation metrices like Hamming-loss are also superior to those of other dimensionality reduction methods. We present a novel framework for multi-label learning that explicitly addresses the challenge arising from the large number of classes and a small size of training data. The key assumption behind this work is that two examples tend to have large overlap in their assigned class memberships if they share high similarity in their input patterns. We capitalize this assumption by first computing two sets of similarities, one based on the input patterns of examples, and the other based on the class memberships of the examples. We then search for the optimal assignment of class memberships to the unlabeled data that minimizes the difference between these two sets of similarities. The optimization problem is formulated as a constrained Non-negative Matrix Factorization (NMF) problem, and an algorithm is presented to efficiently find the solution. Compared to the existing approaches for multi-label learning, the proposed approach is advantageous in that it is able to explore both the unlabeled data and the correlation among different classes simultaneously. Experiments with text categorization show that our approach performs significantly better than several state-of-the-art classification techniques when the number of classes is large and the size of training data is small.