bluuebunny/crossref_metadata_2025 huggingface dataset:
The Off-Switch Game
Authors: Hadfield-Menell Dylan , Dragan Anca , Abbeel Pieter , Russell Stuart
Published: July 2017

It is clear that one of the primary tools we can use to mitigate the potential risk from a misbehaving AI system is the ability to turn the system off. As the capabilities of AI systems improve, it is important to ensure that such systems do not adopt subgoals that prevent a human from switching the system off. This is a challenge because many formulations of rational agents create strong incentives for self-preservation. This is not caused by a built-in instinct, but because a rational agent will maximize expected utility and cannot achieve whatever objective it has been given if it is dead. Our goal is to study the incentives an agent has to allow itself to be switched off. We analyze a simple game between a human H and a robot R, where H can press R’s off switch but R can disable the off switch. A traditional agent takes its reward function for granted: we show that such agents have an incentive to disable the off switch, except in the special case where H is perfectly rational. Our key insight is that for R to want to preserve its off switch, it needs to be uncertain about the utility associated with the outcome, and to treat H’s actions as important observations about that utility. (R also has no incentive to switch itself off in this setting.) We conclude that giving machines an appropriate level of uncertainty about their objectives leads to safer designs, and we argue that this setting is a useful generalization of the classical AI paradigm of rational agents.
Semi-supervised Orthogonal Graph Embedding with Recursive Projections
Authors: Liu Hanyang , Han Junwei , Nie Feiping
Published: July 2017

Many graph based semi-supervised dimensionality reduction algorithms utilize the projection matrix to linearly map the data matrix from the original feature space to a lower dimensional representation. But the dimensionality after reduction is inevitably restricted to the number of classes, and the learned non-orthogonal projection matrix usually fails to preserve distances well and balance the weight on different projection direction. This paper proposes a novel dimensionality reduction method, called the semi-supervised orthogonal graph embedding with recursive projections (SOGE). We integrate the manifold smoothness and label fitness as well as the penalization of the linear mapping mismatch, and learn the orthogonal projection on the Stiefel manifold that empirically demonstrates better performance. Moreover, we recursively update the projection matrix in its orthocomplemented space to continuously learn more projection vectors, so as to better control the dimension of reduction. Comprehensive experiment on several benchmarks demonstrates the significant improvement over the existing methods.
Optimal Posted-Price Mechanism in Microtask Crowdsourcing
Authors: Hu Zehong , Zhang Jie
Published: July 2017

Posted-price mechanisms are widely-adopted to decide the price of tasks in popular microtask crowdsourcing. In this paper, we propose a novel posted-price mechanism which not only outperforms existing mechanisms on performance but also avoids their need of a finite price range. The advantages are achieved by converting the pricing problem into a multi-armed bandit problem and designing an optimal algorithm to exploit the unique features of microtask crowdsourcing. We theoretically show the optimality of our algorithm and prove that the performance upper bound can be achieved without the need of a prior price range. We also conduct extensive experiments using real price data to verify the advantages and practicability of our mechanism.
Dynamic Weighted Majority for Incremental Learning of Imbalanced Data Streams with Concept Drift
Authors: Lu Yang , Cheung Yiu-ming , Tang Yuan Yan
Published: July 2017

Concept drifts occurring in data streams will jeopardize the accuracy and stability of the online learning process. If the data stream is imbalanced, it will be even more challenging to detect and cure the concept drift. In the literature, these two problems have been intensively addressed separately, but have yet to be well studied when they occur together. In this paper, we propose a chunk-based incremental learning method called Dynamic Weighted Majority for Imbalance Learning (DWMIL) to deal with the data streams with concept drift and class imbalance problem. DWMIL utilizes an ensemble framework by dynamically weighting the base classifiers according to their performance on the current data chunk. Compared with the existing methods, its merits are four-fold: (1) it can keep stable for non-drifted streams and quickly adapt to the new concept; (2) it is totally incremental, i.e. no previous data needs to be stored; (3) it keeps a limited number of classifiers to ensure high efficiency; and (4) it is simple and needs only one thresholding parameter. Experiments on both synthetic and real data sets with concept drift show that DWMIL performs better than the state-of-the-art competitors, with less computational cost.
Sampling for Approximate Maximum Search in Factorized Tensor
Authors: Lu Zhi , Hu Yang , Zeng Bing
Published: July 2017

Factorization models have been extensively used for recovering the missing entries of a matrix or tensor. However, directly computing all of the entries using the learned factorization models is prohibitive when the size of the matrix/tensor is large. On the other hand, in many applications, such as collaborative filtering, we are only interested in a few entries that are the largest among them. In this work, we propose a sampling-based approach for finding the top entries of a tensor which is decomposed by the CANDECOMP/PARAFAC model. We develop an algorithm to sample the entries with probabilities proportional to their values. We further extend it to make the sampling proportional to the $k$-th power of the values, amplifying the focus on the top ones. We provide theoretical analysis of the sampling algorithm and evaluate its performance on several real-world data sets. Experimental results indicate that the proposed approach is orders of magnitude faster than exhaustive computing. When applied to the special case of searching in a matrix, it also requires fewer samples than the other state-of-the-art method.
Online Roommate Allocation Problem
Authors: Huzhang Guangda , Huang Xin , Zhang Shengyu , Bei Xiaohui
Published: July 2017

We study the online allocation problem under a roommate market model introduced in [Chan et al., 2016]. Consider a fixed supply of n rooms and a list of 2n applicants arriving sequentially in an online fashion. The problem is to assign a room to each person upon her arrival, such that after the algorithm terminates, each room is shared by exactly two people. We focus on two objectives: (1) maximizing the social welfare, which is defined as the sum of valuations that applicants have for their rooms, plus the happiness value between each pair of roommates; (2) the allocation should satisfy certain stability conditions, such that no group of people would be willing to switch roommates or rooms. We first show a polynomial-time online algorithm that achieves constant competitive ratio for social welfare maximization. We then extend it to the case where each room is assigned to c > 2 people, and achieve a competitive ratio of Ω(1/c^2). Finally, we show both positive and negative results in satisfying different stability conditions in this online setting.
General Heterogeneous Transfer Distance Metric Learning via Knowledge Fragments Transfer
Authors: Luo Yong , Wen Yonggang , Liu Tongliang , Tao Dacheng
Published: July 2017

Transfer learning aims to improve the performance of target learning task by leveraging information (or transferring knowledge) from other related tasks. Recently, transfer distance metric learning (TDML) has attracted lots of interests, but most of these methods assume that feature representations for the source and target learning tasks are the same. Hence, they are not suitable for the applications, in which the data are from heterogeneous domains (feature spaces, modalities and even semantics). Although some existing heterogeneous transfer learning (HTL) approaches is able to handle such domains, they lack flexibility in real-world applications, and the learned transformations are often restricted to be linear. We therefore develop a general and flexible heterogeneous TDML (HTDML) framework based on the knowledge fragment transfer strategy. In the proposed HTDML, any (linear or nonlinear) distance metric learning algorithms can be employed to learn the source metric beforehand. Then a set of knowledge fragments are extracted from the pre-learned source metric to help target metric learning. In addition, either linear or nonlinear distance metric can be learned for the target domain. Extensive experiments on both scene classification and object recognition demonstrate superiority of the proposed method.
Logistic Markov Decision Processes
Authors: Mladenov Martin , Boutilier Craig , Schuurmans Dale , Meshi Ofer , Elidan Gal , Lu Tyler
Published: July 2017

User modeling in advertising and recommendation has typically focused on myopic predictors of user responses. In this work, we consider the long-term decision problem associated with user interaction. We propose a concise specification of long-term interaction dynamics by combining factored dynamic Bayesian networks with logistic predictors of user responses, allowing state-of-the-art prediction models to be seamlessly extended. We show how to solve such models at scale by providing a constraint generation approach for approximate linear programming that overcomes the variable coupling and non-linearity induced by the logistic regression predictor. The efficacy of the approach is demonstrated on advertising domains with up to 2^54 states and 2^39 actions.
Beyond the Nystrom Approximation: Speeding up Spectral Clustering using Uniform Sampling and Weighted Kernel k-means
Authors: Mohan Mahesh , Monteleoni Claire
Published: July 2017

In this paper we present a framework for spectral clustering based on the following simple scheme: sample a subset of the input points, compute the clusters for the sampled subset using weighted kernel k-means (Dhillon et al. 2004) and use the resulting centers to compute a clustering for the remaining data points. For the case where the points are sampled uniformly at random without replacement, we show that the number of samples required depends mainly on the number of clusters and the diameter of the set of points in the kernel space. Experiments show that the proposed framework outperforms the approaches based on the Nystrom approximation both in terms of accuracy and computation time.
Autonomous Task Sequencing for Customized Curriculum Design in Reinforcement Learning
Authors: Narvekar Sanmit , Sinapov Jivko , Stone Peter
Published: July 2017

Transfer learning is a method where an agent reuses knowledge learned in a source task to improve learning on a target task. Recent work has shown that transfer learning can be extended to the idea of curriculum learning, where the agent incrementally accumulates knowledge over a sequence of tasks (i.e. a curriculum). In most existing work, such curricula have been constructed manually. Furthermore, they are fixed ahead of time, and do not adapt to the progress or abilities of the agent. In this paper, we formulate the design of a curriculum as a Markov Decision Process, which directly models the accumulation of knowledge as an agent interacts with tasks, and propose a method that approximates an execution of an optimal policy in this MDP to produce an agent-specific curriculum. We use our approach to automatically sequence tasks for 3 agents with varying sensing and action capabilities in an experimental domain, and show that our method produces curricula customized for each agent that improve performance relative to learning from scratch or using a different agent's curriculum.
Self-weighted Multiview Clustering with Multiple Graphs
Authors: Nie Feiping , Li Jing , Li Xuelong
Published: July 2017

In multiview learning, it is essential to assign a reasonable weight to each view according to its importance. Thus, for multiview clustering task, a wise and elegant method should achieve clustering multiview data while learning the view weights. In this paper, we address this problem by exploring a Laplacian rank constrained graph, which can be approximately as the centroid of the built graph for each view with different confidences. We start our work with a natural thought that the weights can be learned by introducing a hyperparameter. By analyzing the weakness of it, we further propose a new multiview clustering method which is totally self-weighted. Furthermore, once the target graph is obtained in our models, we can directly assign the cluster label to each data point and do not need any postprocessing such as $K$-means in standard spectral clustering. Evaluations on two synthetic datasets prove the effectiveness of our methods. Compared with several representative graph-based multiview clustering approaches on four real-world datasets, experimental results demonstrate that the proposed methods achieve the better performances and our new clustering method is more practical to use.
Boosted Zero-Shot Learning with Semantic Correlation Regularization
Authors: Pi Te , Li Xi , Zhang Zhongfei (Mark)
Published: July 2017

We study zero-shot learning (ZSL) as a transfer learning problem, and focus on the two key aspects of ZSL, model effectiveness and model adaptation. For effective modeling, we adopt the boosting strategy to learn a zero-shot classifier from weak models to a strong model. For adaptable knowledge transfer, we devise a Semantic Correlation Regularization (SCR) approach to regularize the boosted model to be consistent with the inter-class semantic correlations. With SCR embedded in the boosting objective, and with a self-controlled sample selection for learning robustness, we propose a unified framework, Boosted Zero-shot classification with Semantic Correlation Regularization (BZ-SCR). By balancing the SCR-regularized boosted model selection and the self-controlled sample selection, BZ-SCR is capable of capturing both discriminative and adaptable feature-to-class semantic alignments, while ensuring the reliability and adaptability of the learned samples. The experiments on two ZSL datasets show the superiority of BZ-SCR over the state-of-the-arts.
A Dual-Stage Attention-Based Recurrent Neural Network for Time Series Prediction
Authors: Qin Yao , Song Dongjin , Chen Haifeng , Cheng Wei , Jiang Guofei , Cottrell Garrison W.
Published: July 2017

The Nonlinear autoregressive exogenous (NARX) model, which predicts the current value of a time series based upon its previous values as well as the current and past values of multiple driving (exogenous) series, has been studied for decades. Despite the fact that various NARX models have been developed, few of them can capture the long-term temporal dependencies appropriately and select the relevant driving series to make predictions. In this paper, we propose a dual-stage attention-based recurrent neural network (DA-RNN) to address these two issues. In the first stage, we introduce an input attention mechanism to adaptively extract relevant driving series (a.k.a., input features) at each time step by referring to the previous encoder hidden state. In the second stage, we use a temporal attention mechanism to select relevant encoder hidden states across all time steps. With this dual-stage attention scheme, our model can not only make predictions effectively, but can also be easily interpreted. Thorough empirical studies based upon the SML 2010 dataset and the NASDAQ 100 Stock dataset demonstrate that the DA-RNN can outperform state-of-the-art methods for time series prediction.
Robust Softmax Regression for Multi-class Classification with Self-Paced Learning
Authors: Ren Yazhou , Zhao Peng , Sheng Yongpan , Yao Dezhong , Xu Zenglin
Published: July 2017

Softmax regression, a generalization of Logistic regression (LR) in the setting of multi-class classification, has been widely used in many machine learning applications. However, the performance of softmax regression is extremely sensitive to the presence of noisy data and outliers. To address this issue, we propose a model of robust softmax regression (RoSR) originated from the self-paced learning (SPL) paradigm for multi-class classification. Concretely, RoSR equipped with the soft weighting scheme is able to evaluate the importance of each data instance. Then, data instances participate in the classification problem according to their weights. In this way, the influence of noisy data and outliers (which are typically with small weights) can be significantly reduced. However, standard SPL may suffer from the imbalanced class influence problem, where some classes may have little influence in the training process if their instances are not sensitive to the loss. To alleviate this problem, we design two novel soft weighting schemes that assign weights and select instances locally for each class. Experimental results demonstrate the effectiveness of the proposed methods.
Convolutional-Match Networks for Question Answering
Authors: Samothrakis Spyridon , Vodopivec Tom , Fairbank Michael , Fasli Maria
Published: July 2017

In this paper, we present a simple, yet effective, attention and memory mechanism that is reminiscent of Memory Networks and we demonstrate it in question-answering scenarios. Our mechanism is based on four simple premises: a) memories can be formed from word sequences by using convolutional networks; b) distance measurements can be taken at a neuronal level; c) a recursive softmax function can be used for attention; d) extensive weight sharing can help profoundly. We achieve state-of-the-art results in the bAbI tasks, outperforming both Memory Networks and the Differentiable Neural Computer, both in terms of accuracy and stability (i.e. variance) of results.
Learning Multi-level Region Consistency with Dense Multi-label Networks for Semantic Segmentation
Authors: Shen Tong , Lin Guosheng , Shen Chunhua , Reid Ian
Published: July 2017

Semantic image segmentation is a fundamental task in image understanding. Per-pixel semantic labelling of an image benefits greatly from the ability to consider region consistency both locally and globally. However, many Fully Convolutional Network based methods do not impose such consistency, which may give rise to noisy and implausible predictions. We address this issue by proposing a dense multi-label network module that is able to encourage the region consistency at different levels. This simple but effective module can be easily integrated into any semantic segmentation systems. With comprehensive experiments, we show that the dense multi-label can successfully remove the implausible labels and clear the confusion so as to boost the performance of semantic segmentation systems.
Hierarchical LSTM with Adjusted Temporal Attention for Video Captioning
Authors: Song Jingkuan , Gao Lianli , Guo Zhao , Liu Wu , Zhang Dongxiang , Shen Heng Tao
Published: July 2017

Recent progress has been made in using attention based encoder-decoder framework for video captioning. However, most existing decoders apply the attention mechanism to every generated words including both visual words (e.g., “gun” and "shooting“) and non-visual words (e.g. "the“, "a”).However, these non-visual words can be easily predicted using natural language model without considering visual signals or attention.Imposing attention mechanism on non-visual words could mislead and decrease the overall performance of video captioning.To address this issue, we propose a hierarchical LSTM with adjusted temporal attention (hLSTMat) approach for video captioning. Specifically, the proposed framework utilizes the temporal attention for selecting specific frames to predict related words, while the adjusted temporal attention is for deciding whether to depend on the visual information or the language context information. Also, a hierarchical LSTMs is designed to simultaneously consider both low-level visual information and deep semantic information to support the video caption generation. To demonstrate the effectiveness of our proposed framework, we test our method on two prevalent datasets: MSVD and MSR-VTT, and experimental results show that our approach outperforms the state-of-the-art methods on both two datasets.
Forecast the Plausible Paths in Crowd Scenes
Authors: Su Hang , Zhu Jun , Dong Yinpeng , Zhang Bo
Published: July 2017

Forecasting the future plausible paths of pedestrians in crowd scenes is of wide applications, but it still remains as a challenging task due to the complexities and uncertainties of crowd motions. To address these issues, we propose to explore the inherent crowd dynamics via a social-aware recurrent Gaussian process model, which facilitates the path prediction by taking advantages of the interplay between the rich prior knowledge and motion uncertainties. Specifically, we derive a social-aware LSTM to explore the crowd dynamic, resulting in a hidden feature embedding the rich prior in massive data. Afterwards, we integrate the descriptor into deep Gaussian processes with motion uncertainties appropriately harnessed. Crowd motion forecasting is implemented by regressing relative motion against the current positions, yielding the predicted paths based on a functional object associated with a distribution. Extensive experiments on public datasets demonstrate that our method obtains the state-of-the-art performance in both structured and unstructured scenes by exploring the complex and uncertain motion patterns, even if the occlusion is serious or the observed trajectories are noisy.
Scaling Active Search using Linear Similarity Functions
Authors: Venkatesan Sibi , Miller James K. , Schneider Jeff , Dubrawski Artur
Published: July 2017

Active Search has become an increasingly useful tool in information retrieval problems where the goal is to discover as many target elements as possible using only limited label queries. With the advent of big data, there is a growing emphasis on the scalability of such techniques to handle very large and very complex datasets.

In this paper, we consider the problem of Active Search where we are given a similarity function between data points. We look at an algorithm introduced by Wang et al. [Wang et al., 2013] known as Active Search on Graphs and propose crucial modifications which allow it to scale significantly. Their approach selects points by minimizing an energy function over the graph induced by the similarity function on the data. Our modifications require the similarity function to be a dot-product between feature vectors of data points, equivalent to having a linear kernel for the adjacency matrix. With this, we are able to scale tremendously: for n data points, the original algorithm runs in O(n^2) time per iteration while ours runs in only O(nr + r^2) given r-dimensional features.

We also describe a simple alternate approach using a weighted-neighbor predictor which also scales well. In our experiments, we show that our method is competitive with existing semi-supervised approaches. We also briefly discuss conditions under which our algorithm performs well.
Active Learning for Black-Box Semantic Role Labeling with Neural Factors
Authors: Wang Chenguang , Chiticariu Laura , Li Yunyao
Published: July 2017

Active learning is a useful technique for tasks for which unlabeled data is abundant but manual labeling is expensive. One example of such a task is semantic role labeling (SRL), which relies heavily on labels from trained linguistic experts. One challenge in applying active learning algorithms for SRL is that the complete knowledge of the SRL model is often unavailable, against the common assumption that active learning methods are aware of the details of the underlying models. In this paper, we present an active learning framework for black-box SRL models (i.e., models whose details are unknown). In lieu of a query strategy based on model details, we propose a neural query strategy model that embeds both language and semantic information to automatically learn the query strategy from predictions of an SRL model alone. Our experimental results demonstrate the effectiveness of both this new active learning framework and the neural query strategy model.
Obtaining High-Quality Label by Distinguishing between Easy and Hard Items in Crowdsourcing
Authors: Wang Wei , Guo Xiang-Yu , Li Shao-Yuan , Jiang Yuan , Zhou Zhi-Hua
Published: July 2017

Crowdsourcing systems make it possible to hire voluntary workers to label large-scale data by offering them small monetary payments. Usually, the taskmaster requires to collect high-quality labels, while the quality of labels obtained from the crowd may not satisfy this requirement. In this paper, we study the problem of obtaining high-quality labels from the crowd and present an approach of learning the difficulty of items in crowdsourcing, in which we construct a small training set of items with estimated difficulty and then learn a model to predict the difficulty of future items. With the predicted difficulty, we can distinguish between easy and hard items to obtain high-quality labels. For easy items, the quality of their labels inferred from the crowd could be high enough to satisfy the requirement; while for hard items, the crowd could not provide high-quality labels, it is better to choose a more knowledgable crowd or employ specialized workers to label them. The experimental results demonstrate that the proposed approach by learning to distinguish between easy and hard items can significantly improve the label quality.
Cascade Dynamics Modeling with Attention-based Recurrent Neural Network
Authors: Wang Yongqing , Shen Huawei , Liu Shenghua , Gao Jinhua , Cheng Xueqi
Published: July 2017

An ability of modeling and predicting the cascades of resharing is crucial to understanding information propagation and to launching campaign of viral marketing. Conventional methods for cascade prediction heavily depend on the hypothesis of diffusion models, e.g., independent cascade model and linear threshold model. Recently, researchers attempt to circumvent the problem of cascade prediction using sequential models (e.g., recurrent neural network, namely RNN) that do not require knowing the underlying diffusion model. Existing sequential models employ a chain structure to capture the memory effect. However, for cascade prediction, each cascade generally corresponds to a diffusion tree, causing cross-dependence in cascade---one sharing behavior could be triggered by its non-immediate predecessor in the memory chain. In this paper, we propose to an attention-based RNN to capture the cross-dependence in cascade. Furthermore, we introduce a \emph{coverage} strategy to combat the misallocation of attention caused by the memoryless of traditional attention mechanism. Extensive experiments on both synthetic and real world datasets

demonstrate the proposed models outperform state-of-the-art models at both cascade prediction and inferring diffusion tree.
Multiple Indefinite Kernel Learning for Feature Selection
Authors: Xue Hui , Song Yu , Xu Hai-Ming
Published: July 2017

Multiple kernel learning for feature selection (MKL-FS) utilizes kernels to explore complex properties of features and performs better in embedded methods. However, the kernels in MKL-FS are generally limited to be positive definite. In fact, indefinite kernels often emerge in actual applications and can achieve better empirical performance. But due to the non-convexity of indefinite kernels, existing MKL-FS methods are usually inapplicable and the corresponding research is also relatively little. In this paper, we propose a novel multiple indefinite kernel feature selection method (MIK-FS) based on the primal framework of indefinite kernel support vector machine (IKSVM), which applies an indefinite base kernel for each feature and then exerts an l1-norm constraint on kernel combination coefficients to select features automatically. A two-stage algorithm is further presented to optimize the coefficients of IKSVM and kernel combination alternately. In the algorithm, we reformulate the non-convex optimization problem of primal IKSVM as a difference of convex functions (DC) programming and transform the non-convex problem into a convex one with the affine minorization approximation. Experiments on real-world datasets demonstrate that MIK-FS is superior to some related state-of-the-art methods in both feature selection and classification performance.
Crowd Learning: Improving Online Decision Making Using Crowdsourced Data
Authors: Liu Yang , Liu Mingyan
Published: July 2017

We analyze an online learning problem that arises in crowdsourcing systems for users facing crowdsourced data: a user at each discrete time step t can choose K out of a total of N options (bandits), and receives randomly generated rewards dependent on user-specific and option-specific statistics unknown to the user. Each user aims to maximize her expected total rewards over a certain time horizon through a sequence of exploration and exploitation steps. Different from the typical regret/bandit learning setting, in this case a user may also exploit crowdsourced information to augment her learning process, i.e., other users' choices or rewards from using these options. We consider two scenarios, one in which only their choices are shared, and the other in which users share full information including their choices and subsequent rewards. In both cases we derive bounds on the weak regret, the difference between the user's expected total reward and the reward from a user-specific best single-action policy; and show how they improve over their individual-learning counterpart. We also evaluate the performance of our algorithms using simulated data as well as the real-world movie ratings dataset MovieLens.
Modal Consistency based Pre-Trained Multi-Model Reuse
Authors: Yang Yang , Zhan De-Chuan , Guo Xiang-Yu , Jiang Yuan
Published: July 2017

Multi-Model Reuse is one of the prominent problems in Learnware framework, while the main issue of Multi-Model Reuse lies in the final prediction acquisition from the responses of multiple pre-trained models. Different from multi-classifiers ensemble, there are only pre-trained models rather than the whole training sets provided in Multi-Model Reuse configuration. This configuration is closer to the real applications where the reliability of each model cannot be evaluated properly. In this paper, aiming at the lack of evaluation on reliability, the potential consistency spread on different modalities is utilized. With the consistency of pre-trained models on different modalities, we propose a Pre-trained Multi-Model Reuse approach PM2R with multi-modal data, which realizes the reusability of multiple models. PM2R can combine pre-trained multi-models efficiently without re-training, and consequently no more training data storage is required. We describe the more realistic Multi-Model Reuse setting comprehensively in our paper, and point out the differences among this setting, classifier ensemble and later fusion on multi-modal learning. Experiments on synthetic and real-world datasets validate the effectiveness of PM2R when it is compared with state-of-the-art ensemble/multi-modal learning methods under this more realistic setting.
A Deep Neural Network for Chinese Zero Pronoun Resolution
Authors: Yin Qingyu , Zhang Weinan , Zhang Yu , Liu Ting
Published: July 2017

Existing approaches for Chinese zero pronoun resolution overlook semantic information. This is because zero pronouns have no descriptive information, which results in difficulty in explicitly capturing their semantic similarities with antecedents. Moreover, when dealing with candidate antecedents, traditional systems simply take advantage of the local information of a single candidate antecedent while failing to consider the underlying information provided by the other candidates from a global perspective. To address these weaknesses, we propose a novel zero pronoun-specific neural network, which is capable of representing zero pronouns by utilizing the contextual information at the semantic level. In addition, when dealing with candidate antecedents, a two-level candidate encoder is employed to explicitly capture both the local and global information of candidate antecedents. We conduct experiments on the Chinese portion of the OntoNotes 5.0 corpus. Experimental results show that our approach substantially outperforms the state-of-the-art method in various experimental settings.
ME-MD: An Effective Framework for Neural Machine Translation with Multiple Encoders and Decoders
Authors: Zhang Jinchao , Liu Qun , Zhou Jie
Published: July 2017

The encoder-decoder neural framework is widely employed for Neural Machine Translation (NMT) with a single encoder to represent the source sentence and a single decoder to generate target words. The translation performance heavily relies on the representation ability of the encoder and the generation ability of the decoder. To further enhance NMT, we propose to extend the original encoder-decoder framework to a novel one, which has multiple encoders and decoders (ME-MD). Through this way, multiple encoders extract more diverse features to represent the source sequence and multiple decoders capture more complicated translation knowledge. Our proposed ME-MD framework is convenient to integrate heterogeneous encoders and decoders with multiple depths and multiple types. Experiment on Chinese-English translation task shows that our ME-MD system surpasses the state-of-the-art NMT system by 2.1 BLEU points and surpasses the phrase-based Moses by 7.38 BLEU points. Our framework is general and can be applied to other sequence to sequence tasks.
DRLnet: Deep Difference Representation Learning Network and An Unsupervised Optimization Framework
Authors: Zhang Puzhao , Gong Maoguo , Zhang Hui , Liu Jia
Published: July 2017

Change detection and analysis (CDA) is an important research topic in the joint interpretation of spatial-temporal remote sensing images. The core of CDA is to effectively represent the difference and measure the difference degree between bi-temporal images. In this paper, we propose a novel difference representation learning network (DRLnet) and an effective optimization framework without any supervision. Difference measurement, difference representation learning and unsupervised clustering are combined as a single model, i.e., DRLnet, which is driven to learn clustering-friendly and discriminative difference representations (DRs) for different types of changes. Further, DRLnet is extended into a recurrent learning framework to update and reuse

limited training samples and prevent the semantic gaps caused by the saltation in the number of change types from over-clustering stage to the desired one. Experimental results identify the effectiveness of the proposed framework.
Global-residual and Local-boundary Refinement Networks for Rectifying Scene Parsing Predictions
Authors: Zhang Rui , Tang Sheng , Lin Min , Li Jintao , Yan Shuicheng
Published: July 2017

Most of existing scene parsing methods suffer from the serious problems of both inconsistent parsing results and object boundary shift. To tackle these problems, we first propose an iterative Global-residual Refinement Network (GRN) through exploiting global contextual information to predict the parsing residuals and iteratively smoothen the inconsistent parsing labels. Furthermore, we propose a Local-boundary Refinement Network (LRN) to learn the position-adaptive propagation coefficients so that local contextual information from neighbors can be optimally captured for refining object boundaries. Finally, we cascade the proposed two refinement networks after a fully residual convolutional neural network within a uniform framework. Extensive experiments on ADE20K and Cityscapes datasets well demonstrate the effectiveness of the two refinement methods for refining scene parsing predictions.
Weighted Double Q-learning
Authors: Zhang Zongzhang , Pan Zhiyuan , Kochenderfer Mykel J.
Published: July 2017

Q-learning is a popular reinforcement learning algorithm, but it can perform poorly in stochastic environments due to overestimating action values. Overestimation is due to the use of a single estimator that uses the maximum action value as an approximation for the maximum expected action value. To avoid overestimation in Q-learning, the double Q-learning algorithm was recently proposed, which uses the double estimator method. It uses two estimators from independent sets of experiences, with one estimator determining the maximizing action and the other providing the estimate of its value. Double Q-learning sometimes underestimates the action values. This paper introduces a weighted double Q-learning algorithm, which is based on the construction of the weighted double estimator, with the goal of balancing between the overestimation in the single estimator and the underestimation in the double estimator. Empirically, the new algorithm is shown to perform well on several MDP problems.
Tensor Based Knowledge Transfer Across Skill Categories for Robot Control
Authors: Zhao Chenyang , Hospedales Timothy M. , Stulp Freek , Sigaud Olivier
Published: July 2017

Advances in hardware and learning for control are enabling robots to perform increasingly dextrous and dynamic control tasks. These skills typically require a prohibitive amount of exploration for reinforcement learning, and so are commonly achieved by imitation learning from manual demonstration. The costly non-scalable nature of manual demonstration has motivated work into skill generalisation, e.g., through contextual policies and options. Despite good results, existing work along these lines is limited to generalising across variants of one skill such as throwing an object to different locations. In this paper we go significantly further and investigate generalisation across qualitatively different classes of control skills. In particular, we introduce a class of neural network controllers that can realise four distinct skill classes: reaching, object throwing, casting, and ball-in-cup. By factorising the weights of the neural network, we are able to extract transferrable latent skills, that enable dramatic acceleration of learning in cross-task transfer. With a suitable curriculum, this allows us to learn challenging dextrous control tasks like ball-in-cup from scratch with pure reinforcement learning.
Random Shifting for CNN: a Solution to Reduce Information Loss in Down-Sampling Layers
Authors: Zhao Gangming , Wang Jingdong , Zhang Zhaoxiang
Published: July 2017

Down-sampling is widely adopted in deep convolutional neural networks (DCNN) for reducing the number of network parameters while preserving the transformation invariance. However, it cannot utilize information effectively because it only adopts a fixed stride strategy, which may result in poor generalization ability and information loss. In this paper, we propose a novel random strategy to alleviate these problems by embedding random shifting in the down-sampling layers during the training process. Random shifting can be universally applied to diverse DCNN models to dynamically adjust receptive fields by shifting kernel centers on feature maps in different directions. Thus, it can generate more robust features in networks and further enhance the transformation invariance of down-sampling operators. In addition, random shifting cannot only be integrated in all down-sampling layers including strided convolutional layers and pooling layers, but also improve performance of DCNN with negligible additional computational cost. We evaluate our method in different tasks (e.g., image classification and segmentation) with various network architectures (i.e., AlexNet, FCN and DFN-MR). Experimental results demonstrate the effectiveness of our proposed method.
Deep Graphical Feature Learning for Face Sketch Synthesis
Authors: Zhu Mingrui , Wang Nannan , Gao Xinbo , Li Jie
Published: July 2017

The exemplar-based face sketch synthesis method generally contains two steps: neighbor

selection and reconstruction weight representation. Pixel intensities are widely used

as features by most of the existing exemplar-based methods, which lacks of representation

ability and robustness to light variations and clutter backgrounds. We present a novel

face sketch synthesis method combining generative exemplar-based method and discriminatively

trained deep convolutional neural networks (dCNNs) via a deep graphical feature learning

framework. Our method works in both two steps by using deep discriminative representations

derived from dCNNs. Instead of using it directly, we boost its representation capability

by a deep graphical feature learning framework. Finally, the optimal weights of deep

representations and optimal reconstruction weights for face sketch synthesis can be

obtained simultaneously. With the optimal reconstruction weights, we can synthesize

high quality sketches which is robust against light variations and clutter backgrounds.

Extensive experiments on public face sketch databases show that our method outperforms

state-of-the-art methods, in terms of both synthesis quality and recognition ability.
Adaptive Hypergraph Learning for Unsupervised Feature Selection
Authors: Zhu Xiaofeng , Zhu Yonghua , Zhang Shichao , Hu Rongyao , He Wei
Published: July 2017

Current unsupervised feature selection (UFS) methods learn the similarity matrix by using a simple graph which is learnt from the original data as well as is independent from the process of feature selection, and thus unable to efficiently remove the redundant/irrelevant features. To address these issues, we propose a new UFS method to jointly learn the similarity matrix and conduct both subspace learning (via learning a dynamic hypergraph) and feature selection (via a sparsity constraint). As a result, we reduce the feature dimensions using different methods (i.e., subspace learning and feature selection) from different feature spaces, and thus makes our method select the informative features effectively and robustly. We tested our method using benchmark datasets to conduct the clustering tasks using the selected features, and the experimental results show that our proposed method outperforms all the comparison methods.
No Learner Left Behind: On the Complexity of Teaching Multiple Learners Simultaneously
Authors: Zhu Xiaojin , Liu Ji , Lopes Manuel
Published: July 2017

We present a theoretical study of algorithmic teaching in the setting where the teacher must use the same training set to teach multiple learners. This problem is a theoretical abstraction of the real-world classroom setting in which the teacher delivers the same lecture to academically diverse students. We define a minimax teaching criterion to guarantee the performance of the worst learner in the class. We prove that the teaching dimension increases with class diversity in general. For the classes of conjugate Bayesian learners and linear regression learners, respectively, we exhibit corresponding minimax teaching set. We then propose a method to enhance teaching by partitioning the class into sections. We present cases where the optimal partition minimizes overall teaching dimension while maintaining the guarantee on all learners. Interestingly, we show personalized education (one learner per section) is not necessarily the optimal partition. Our results generalize algorithmic teaching to multiple learners and offer insight on how to teach large classes.
What to Do Next: Modeling User Behaviors by Time-LSTM
Authors: Zhu Yu , Li Hao , Liao Yikang , Wang Beidou , Guan Ziyu , Liu Haifeng , Cai Deng
Published: July 2017

Recently, Recurrent Neural Network (RNN) solutions for recommender systems (RS) are becoming increasingly popular. The insight is that, there exist some intrinsic patterns in the sequence of users' actions, and RNN has been proved to perform excellently when modeling sequential data. In traditional tasks such as language modeling, RNN solutions usually only consider the sequential order of objects without the notion of interval. However, in RS, time intervals between users' actions are of significant importance in capturing the relations of users' actions and the traditional RNN architectures are not good at modeling them. In this paper, we propose a new LSTM variant, i.e. Time-LSTM, to model users' sequential actions. Time-LSTM equips LSTM with time gates to model time intervals. These time gates are specifically designed, so that compared to the traditional RNN solutions, Time-LSTM better captures both of users' short-term and long-term interests, so as to improve the recommendation performance. Experimental results on two real-world datasets show the superiority of the recommendation method using Time-LSTM over the traditional methods.
Object Recognition with and without Objects
Authors: Zhu Zhuotun , Xie Lingxi , Yuille Alan
Published: July 2017

While recent deep neural networks have achieved a promising performance on object recognition, they rely implicitly on the visual contents of the whole image. In this paper, we train deep neural networks on the foreground (object) and background (context) regions of images respectively. Considering human recognition in the same situations, networks trained on the pure background without objects achieves highly reasonable recognition performance that beats humans by a large margin if only given context. However, humans still outperform networks with pure object available, which indicates networks and human beings have different mechanisms in understanding an image. Furthermore, we straightforwardly combine multiple trained networks to explore different visual cues learned by different networks. Experiments show that useful visual hints can be explicitly learned separately and then combined to achieve higher performance, which verifies the advantages of the proposed framework.
Opinion-aware Knowledge Graph for Political Ideology Detection
Authors: Chen Wei , Zhang Xiao , Wang Tengjiao , Yang Bishan , Li Yi
Published: July 2017

Identifying individual's political ideology from their speeches and written texts is important for analyzing political opinions and user behavior on social media. Traditional opinion mining methods rely on bag-of-words representations to classify texts into different ideology categories. Such methods are too coarse for understanding political ideologies. The key to identify different ideologies is to recognize different opinions expressed toward a specific topic. To model this insight, we classify ideologies based on the distribution of opinions expressed towards real-world entities or topics. Specifically, we propose a novel approach to political ideology detection that makes predictions based on an opinion-aware knowledge graph. We show how to construct such graph by integrating the opinions and targeted entities extracted from text into an existing structured knowledge base, and show how to perform ideology inference by information propagation on the graph. Experimental results demonstrate that our method achieves high accuracy in detecting ideologies compared to baselines including LR, SVM and RNN.