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"Topic": models, code, and papers

Personalization in Goal-Oriented Dialog

Dec 15, 2017
Chaitanya K. Joshi, Fei Mi, Boi Faltings

The main goal of modeling human conversation is to create agents which can interact with people in both open-ended and goal-oriented scenarios. End-to-end trained neural dialog systems are an important line of research for such generalized dialog models as they do not resort to any situation-specific handcrafting of rules. However, incorporating personalization into such systems is a largely unexplored topic as there are no existing corpora to facilitate such work. In this paper, we present a new dataset of goal-oriented dialogs which are influenced by speaker profiles attached to them. We analyze the shortcomings of an existing end-to-end dialog system based on Memory Networks and propose modifications to the architecture which enable personalization. We also investigate personalization in dialog as a multi-task learning problem, and show that a single model which shares features among various profiles outperforms separate models for each profile.

* Accepted at NIPS 2017 Conversational AI Workshop; Code and data at 

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Applying Data Augmentation to Handwritten Arabic Numeral Recognition Using Deep Learning Neural Networks

Sep 27, 2017
Akm Ashiquzzaman, Abdul Kawsar Tushar, Ashiqur Rahman

Handwritten character recognition has been the center of research and a benchmark problem in the sector of pattern recognition and artificial intelligence, and it continues to be a challenging research topic. Due to its enormous application many works have been done in this field focusing on different languages. Arabic, being a diversified language has a huge scope of research with potential challenges. A convolutional neural network model for recognizing handwritten numerals in Arabic language is proposed in this paper, where the dataset is subject to various augmentation in order to add robustness needed for deep learning approach. The proposed method is empowered by the presence of dropout regularization to do away with the problem of data overfitting. Moreover, suitable change is introduced in activation function to overcome the problem of vanishing gradient. With these modifications, the proposed system achieves an accuracy of 99.4\% which performs better than every previous work on the dataset.

* 5 pages, 6 figures, 3 tables 

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Poisson Random Fields for Dynamic Feature Models

Nov 22, 2016
Valerio Perrone, Paul A. Jenkins, Dario Spano, Yee Whye Teh

We present the Wright-Fisher Indian buffet process (WF-IBP), a probabilistic model for time-dependent data assumed to have been generated by an unknown number of latent features. This model is suitable as a prior in Bayesian nonparametric feature allocation models in which the features underlying the observed data exhibit a dependency structure over time. More specifically, we establish a new framework for generating dependent Indian buffet processes, where the Poisson random field model from population genetics is used as a way of constructing dependent beta processes. Inference in the model is complex, and we describe a sophisticated Markov Chain Monte Carlo algorithm for exact posterior simulation. We apply our construction to develop a nonparametric focused topic model for collections of time-stamped text documents and test it on the full corpus of NIPS papers published from 1987 to 2015.

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Clustering Comparable Corpora of Russian and Ukrainian Academic Texts: Word Embeddings and Semantic Fingerprints

Apr 18, 2016
Andrey Kutuzov, Mikhail Kopotev, Tatyana Sviridenko, Lyubov Ivanova

We present our experience in applying distributional semantics (neural word embeddings) to the problem of representing and clustering documents in a bilingual comparable corpus. Our data is a collection of Russian and Ukrainian academic texts, for which topics are their academic fields. In order to build language-independent semantic representations of these documents, we train neural distributional models on monolingual corpora and learn the optimal linear transformation of vectors from one language to another. The resulting vectors are then used to produce `semantic fingerprints' of documents, serving as input to a clustering algorithm. The presented method is compared to several baselines including `orthographic translation' with Levenshtein edit distance and outperforms them by a large margin. We also show that language-independent `semantic fingerprints' are superior to multi-lingual clustering algorithms proposed in the previous work, at the same time requiring less linguistic resources.

* To be presented at 9th Workshop on Building and Using Comparable Corpora, co-located with LREC-2016 (

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Embracing Error to Enable Rapid Crowdsourcing

Feb 14, 2016
Ranjay Krishna, Kenji Hata, Stephanie Chen, Joshua Kravitz, David A. Shamma, Li Fei-Fei, Michael S. Bernstein

Microtask crowdsourcing has enabled dataset advances in social science and machine learning, but existing crowdsourcing schemes are too expensive to scale up with the expanding volume of data. To scale and widen the applicability of crowdsourcing, we present a technique that produces extremely rapid judgments for binary and categorical labels. Rather than punishing all errors, which causes workers to proceed slowly and deliberately, our technique speeds up workers' judgments to the point where errors are acceptable and even expected. We demonstrate that it is possible to rectify these errors by randomizing task order and modeling response latency. We evaluate our technique on a breadth of common labeling tasks such as image verification, word similarity, sentiment analysis and topic classification. Where prior work typically achieves a 0.25x to 1x speedup over fixed majority vote, our approach often achieves an order of magnitude (10x) speedup.

* 10 pages, 7 figures, CHI '16, CHI: ACM Conference on Human Factors in Computing Systems (2016) 

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Confounds and Consequences in Geotagged Twitter Data

Aug 22, 2015
Umashanthi Pavalanathan, Jacob Eisenstein

Twitter is often used in quantitative studies that identify geographically-preferred topics, writing styles, and entities. These studies rely on either GPS coordinates attached to individual messages, or on the user-supplied location field in each profile. In this paper, we compare these data acquisition techniques and quantify the biases that they introduce; we also measure their effects on linguistic analysis and text-based geolocation. GPS-tagging and self-reported locations yield measurably different corpora, and these linguistic differences are partially attributable to differences in dataset composition by age and gender. Using a latent variable model to induce age and gender, we show how these demographic variables interact with geography to affect language use. We also show that the accuracy of text-based geolocation varies with population demographics, giving the best results for men above the age of 40.

* final version for EMNLP 2015 

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Is Stack Overflow Overflowing With Questions and Tags

Aug 14, 2015
Ranjitha R. K., Sanjay Singh

Programming question and answer (Q & A) websites, such as Quora, Stack Overflow, and Yahoo! Answer etc. helps us to understand the programming concepts easily and quickly in a way that has been tested and applied by many software developers. Stack Overflow is one of the most frequently used programming Q\&A website where the questions and answers posted are presently analyzed manually, which requires a huge amount of time and resource. To save the effort, we present a topic modeling based technique to analyze the words of the original texts to discover the themes that run through them. We also propose a method to automate the process of reviewing the quality of questions on Stack Overflow dataset in order to avoid ballooning the stack overflow with insignificant questions. The proposed method also recommends the appropriate tags for the new post, which averts the creation of unnecessary tags on Stack Overflow.

* 11 pages, 7 figures, 3 tables Presented at Third International Symposium on Women in Computing and Informatics (WCI-2015) 

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Parallel Magnetic Resonance Imaging

Jul 17, 2015
Martin Uecker

The main disadvantage of Magnetic Resonance Imaging (MRI) are its long scan times and, in consequence, its sensitivity to motion. Exploiting the complementary information from multiple receive coils, parallel imaging is able to recover images from under-sampled k-space data and to accelerate the measurement. Because parallel magnetic resonance imaging can be used to accelerate basically any imaging sequence it has many important applications. Parallel imaging brought a fundamental shift in image reconstruction: Image reconstruction changed from a simple direct Fourier transform to the solution of an ill-conditioned inverse problem. This work gives an overview of image reconstruction from the perspective of inverse problems. After introducing basic concepts such as regularization, discretization, and iterative reconstruction, advanced topics are discussed including algorithms for auto-calibration, the connection to approximation theory, and the combination with compressed sensing.

* In: MRI: Physics, Image Reconstruction, and Analysis, CRC Press 2015, pp. 73-92, ISBN 9781482298871 
* 22 pages, 9 Figures, 76 References. Copyright: Martin Uecker. Draft for a book chapter. To appear in: A Majumdar and RK Ward (eds.), MRI: Physics, Image Reconstruction, and Analysis, CRC Press 2015 

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Rediscovering the Alphabet - On the Innate Universal Grammar

Dec 08, 2014
M. Yahia Kaadan, Asaad Kaadan

Universal Grammar (UG) theory has been one of the most important research topics in linguistics since introduced five decades ago. UG specifies the restricted set of languages learnable by human brain, and thus, many researchers believe in its biological roots. Numerous empirical studies of neurobiological and cognitive functions of the human brain, and of many natural languages, have been conducted to unveil some aspects of UG. This, however, resulted in different and sometimes contradicting theories that do not indicate a universally unique grammar. In this research, we tackle the UG problem from an entirely different perspective. We search for the Unique Universal Grammar (UUG) that facilitates communication and knowledge transfer, the sole purpose of a language. We formulate this UG and show that it is unique, intrinsic, and cosmic, rather than humanistic. Initial analysis on a widespread natural language already showed some positive results.

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Reading Stockholm Riots 2013 in social media by text-mining

Oct 04, 2013
Andrzej Jarynowski, Amir Rostami

The riots in Stockholm in May 2013 were an event that reverberated in the world media for its dimension of violence that had spread through the Swedish capital. In this study we have investigated the role of social media in creating media phenomena via text mining and natural language processing. We have focused on two channels of communication for our analysis: Twitter and (Forum of Polish community in Sweden). Our preliminary results show some hot topics driving discussion related mostly to Swedish Police and Swedish Politics by counting word usage. Typical features for media intervention are presented. We have built networks of most popular phrases, clustered by categories (geography, media institution, etc.). Sentiment analysis shows negative connotation with Police. The aim of this preliminary exploratory quantitative study was to generate questions and hypotheses, which we could carefully follow by deeper more qualitative methods.

* 5p 

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