University of California, San Diego
Multi-Task Medical Concept Normalization Using Multi-View Convolutional Neural Network
Luo, Yi (University of California, San Diego) | Song, Guojie (Peking University) | Li, Pengyu (Peking University) | Qi, Zhongang (Oregon State University)
Medical concept normalization is a critical problem in biomedical research and clinical applications. In this paper, we focus on normalizing diagnostic and procedure names in Chinese discharge summaries to standard entities, which is formulated as a semantic matching problem. However, non-standard Chinese expressions, short-text normalization and heterogeneity of tasks pose critical challenges in our problem. This paper presents a general framework which introduces a tensor generator and a novel multi-view convolutional neural network (CNN) with multi-task shared structure to tackle the two tasks simultaneously. We propose that the key to address non-standard expressions and short-text problem is to incorporate a matching tensor with multiple granularities. Then multi-view CNN is adopted to extract semantic matching patterns and learn to synthesize them from different views. Finally, multi-task shared structure allows the model to exploit medical correlations between disease and procedure names to better perform disambiguation tasks. Comprehensive experimental analysis indicates our model outperforms existing baselines which demonstrates the effectiveness of our model.
Theoretical Concerns for the Integration of Repair
Trott, Sean (University of California, San Diego) | Rossano, Federico (University of California, San Diego)
Human conversation is messy. Speakers frequently repair their speech, and listeners must therefore integrate information across ill-formed, often fragmentary inputs. Previous dialogue systems for human-robot interaction (HRI) have addressed certain problems in dialogue repair, but there are many problems that remain. In this paper, we discuss these problems from the perspective of Conversation Analysis, and argue that a more holistic account of dialogue repair will actually aid in the design and implementation of machine dialogue systems.
A Theoretical Model of Indirect Request Comprehension
Trott, Sean (University of California, San Diego) | Bergen, Benjamin (University of California, San Diego)
Natural human dialogue often contains ambiguous or indirect speech. This poses a unique challenge to language understanding systems because comprehension requires going beyond what is said to what is implied. In this paper, we survey related work on the particularly challenging case of understanding non-conventional indirect speech acts, then propose a more generalizable rule rooted in building a mental model of the speaker. Finally, we discuss experimental evidence pointing to the cognitive plausibility of this rule.
Using Deep and Convolutional Neural Networks for Accurate Emotion Classification on DEAP Dataset.
Tripathi, Samarth (Columbia University) | Acharya, Shrinivas (Amazon, Hyderabad) | Sharma, Ranti Dev (University of California, San Diego) | Mittal, Sudhanshu (Oracle, Hyderabad) | Bhattacharya, Samit (Indian Institute of Technology, Guwahati)
Emotion recognition is an important field of research in Brain Computer Interactions. As technology and the understanding of emotions are advancing, there are growing opportunities for automatic emotion recognition systems. Neural networks are a family of statistical learning models inspired by biological neural networks and are used to estimate functions that can depend on a large number of inputs that are generally unknown. In this paper we seek to use this effectiveness of Neural Networks to classify user emotions using EEG signals from the DEAP (Koelstra et al (2012)) dataset which represents the benchmark for Emotion classification research. We explore 2 different Neural Models, a simple Deep Neural Network and a Convolutional Neural Network for classification. Our model provides the state-of-the-art classification accuracy, obtaining 4.51 and 4.96 percentage point improvements over (Rozgic et al (2013)) classification of Valence and Arousal into 2 classes (High and Low) and 13.39 and 6.58 percentage point improvements over (Chung and Yoon(2012)) classification of Valence and Arousal into 3 classes (High, Normal and Low). Moreover our research is a testament that Neural Networks could be robust classifiers for brain signals, even outperforming traditional learning techniques.
Solving Constrained Combinatorial Optimisation Problems via MAP Inference without High-Order Penalties
Zhang, Zhen (Northwestern Polytechnical University) | Shi, Qinfeng (The University of Adelaide) | McAuley, Julian (University of California, San Diego) | Wei, Wei (Northwestern Polytechnical University) | Zhang, Yanning (Northwestern Polytechnical University) | Yao, Rui (China University of Mining and Technology) | Hengel, Anton van den (The University of Adelaide)
Solving constrained combinatorial optimisation problems via MAP inference is often achieved by introducing extra potential functions for each constraint. This can result in very high order potentials, e.g. a 2nd-order objective with pairwise potentials and a quadratic constraint over all N variables would correspond to an unconstrained objective with an order-N potential. This limits the practicality of such an approach, since inference with high order potentials is tractable only for a few special classes of functions. We propose an approach which is able to solve constrained combinatorial problems using belief propagation without increasing the order. For example, in our scheme the 2nd-order problem above remains order 2 instead of order N. Experiments on applications ranging from foreground detection, image reconstruction, quadratic knapsack, and the M-best solutions problem demonstrate the effectiveness and efficiency of our method. Moreover, we show several situations in which our approach outperforms commercial solvers like CPLEX and others designed for specific constrained MAP inference problems.
Capturing Planned Protests from Open Source Indicators
Muthiah, Sathappan (Virginia Polytechnic Institute and State University.) | Huang, Bert (Virginia Polytechnic Institute and State University.) | Arredondo, Jaime (University of California, San Diego) | Mares, David (University of California, San Diego) | Getoor, Lise (University of California, Santa Cruz) | Katz, Graham (IBM, Inc.) | Ramakrishnan, Naren (Virginia Polytechnic Institute and State University.)
Civil unrest events (protests, strikes, and โoccupyโ events) are common occurrences in both democracies and authoritarian regimes. The study of civil unrest is a key topic for political scientists as it helps capture an important mechanism by which citizenry express themselves. In countries where civil unrest is lawful, qualitative analysis has revealed that more than 75 percent of the protests are planned, organized, or announced in advance; therefore detecting references to future planned events in relevant news and social media is a direct way to develop a protest forecasting system. We report on a system for doing that in this article. It uses a combination of keyphrase learning to identify what to look for, probabilistic soft logic to reason about location occurrences in extracted results, and time normalization to resolve future time mentions. We illustrate the application of our system to 10 countries in Latin America: Argentina, Brazil, Chile, Colombia, Ecuador, El Salvador, Mexico, Paraguay, Uruguay, and Venezuela. Results demonstrate our successes in capturing significant societal unrest in these countries with an average lead time of 4.08 days. We also study the selective superiorities of news media versus social media (Twitter, Facebook) to identify relevant trade-offs.
VBPR: Visual Bayesian Personalized Ranking from Implicit Feedback
He, Ruining (University of California, San Diego) | McAuley, Julian ( University of California, San Diego )
Modern recommender systems model people and items by discovering or `teasing apart' the underlying dimensions that encode the properties of items and users' preferences toward them. Critically, such dimensions are uncovered based on user feedback, often in implicit form (such as purchase histories, browsing logs, etc.); in addition, some recommender systems make use of side information, such as product attributes, temporal information, or review text.However one important feature that is typically ignored by existing personalized recommendation and ranking methods is the visual appearance of the items being considered. In this paper we propose a scalable factorization model to incorporate visual signals into predictors of people's opinions, which we apply to a selection of large, real-world datasets. We make use of visual features extracted from product images using (pre-trained) deep networks, on top of which we learn an additional layer that uncovers the visual dimensions that best explain the variation in people's feedback. This not only leads to significantly more accurate personalized ranking methods, but also helps to alleviate cold start issues, and qualitatively to analyze the visual dimensions that influence people's opinions.
Crowdsourcing Feature Discovery via Adaptively Chosen Comparisons
Zou, James (Microsoft Research) | Chaudhuri, Kamalika (University of California, San Diego) | Kalai, Adam (Microsoft Research)
We introduce an unsupervised approach to efficiently discover the underlying features in a data set via crowdsourcing. Our queries ask crowd members to articulate a feature common to two out of three displayed examples. In addition, we ask the crowd to provide binary labels for these discovered features on the remaining examples. The triples are chosen adaptively based on the labels of the previously discovered features on the data set. This approach is motivated by a formal framework of feature elicitation that we introduce and analyze in this paper. In two natural models of features, hierarchical and independent, we show that a simple adaptive algorithm recovers all features with less labor than any nonadaptive algorithm. The savings are as a result of automatically avoiding the elicitation of redundant features or synonyms. Experimental results validate the theoretical findings and the usefulness of this approach.
SmartShift: Expanded Load Shifting Incentive Mechanism for Risk-Averse Consumers
Shen, Bochao (Northeastern University) | Narayanaswamy, Balakrishnan (University of California, San Diego) | Sundaram, Ravi (Northeastern University)
Peak demand for electricity continues to surge around the world. The supply-demand imbalance manifests itself in many forms, from rolling brownouts in California to power cuts in India. It is often suggested that exposing consumers to real-time pricing, will incentivize them to change their usage and mitigate the problem - akin to increasing tolls at peak commute times. We show that risk-averse consumers of electricity react to price fluctuations by scaling back on their total demand, not just their peak demand, leading to the unintended consequence of an overall decrease in production/consumption and reduced economic efficiency. We propose a new scheme that allows homes to move their demands from peak hours in exchange for greater electricity consumption in non-peak hours - akin to how airlines incentivize a passenger to move from an over-booked flight in exchange for, say, two tickets in the future. We present a formal framework for the incentive model that is applicable to different forms of the electricity market. We show that our scheme not only enables increased consumption and consumer social welfare but also allows the distribution company to increase profits. This is achieved by allowing load to be shifted while insulating consumers from real-time price fluctuations. This win-win is important if these methods are to be embraced in practice.
Cost-Effective HITs for Relative Similarity Comparisons
Wilber, Michael J. (Cornell University) | Kwak, Iljung S. (University of California, San Diego) | Belongie, Serge J. (Cornell University)
Similarity comparisons of the form "Is object a more similar to b than to c?" form a useful foundation in several computer vision and machine learning applications. Unfortunately, an embedding of n points is only uniquely specified by n 3 triplets, making collecting every triplet an expensive task. In noticing this difficulty, other researchers investigated more intelligent triplet sampling techniques, but they do not study their effectiveness or their potential drawbacks. Although it is important to reduce the number of collected triplets to generate a good embedding, it is also important to understand how best to display a triplet collection task to the user to better respect the worker's human constraints. In this work, we explore an alternative method for collecting triplets and analyze its financial cost, collection speed, and worker happiness as a function of the final embedding quality. We propose best practices for creating cost effective human intelligence tasks for collecting triplets. We show that rather than changing the sampling algorithm, simple changes to the crowdsourcing UI can drastically decrease the cost of collecting similarity comparisons. Finally, we provide a food similarity dataset as well as the labels collected from crowd workers.