Acquiring Knowledge from Multimodal Sources to Aid Language Understanding    Posted:

Date : 8 March 2017, 14:00 , Room A008

Speaker: Marie-Francine Moens

Abstract : Human language understanding (HLU) by a machine is of large economic and social value. In this lecture we consider language understanding of written text. First, we give an overview of the latest methods for HLU that map language to a formal knowledge representation which facilitates other automated tasks. Most current HLU systems are trained on texts that are manually annotated, which are often lacking in open domain applications. In addition, much content is left implicit in a text, which when humans read a text is inferred by relying on their world and common sense knowledge. We go deeper into the field of representation learning that nowadays is very much studied in computational linguistics. This field investigates methods for representing language as statistical concepts or as vectors, allowing straightforward methods of compositionality. The methods often use deep learning and its underlying neural network technologies to learn concepts from large text collections in an unsupervised way (i.e., without the need for manual annotations). We show how these methods can help, but also demonstrate that these methods are still insufficient to automatically acquire the necessary background knowledge and more specifically world and common sense knowledge needed for language understanding. We go deeper in on how we can learn knowledge jointly from textual and visual data to help language understanding, which will be illustrated with the first results obtained in the MUSTER CHIST-ERA project.


A review of NIPS 2016    Posted:

Date : 3 February 2017, 14:00 am, Room C005

Speaker: Hoa Le Thien

Abstract : In this talk, I will discuss the main hot topics of the AI & Deep Learning community research right now such as : Deep Reinforcement Learning, Generative Adversarial Networks (GAN), Limitations of RNNs, Obstacles of Deep Learning & NLP, Learning to Learn,... The aim of the presentation is to give you a rigorous framework & most updated elements for the future direction of research. This will include the inspiration from differents fields (like robotics, computer vision,...) and the direct implementation in NLP.


Distributional Semantic Spaces: Creation and Applications    Posted:

Date: 30 November, 2016, 14:00

Speaker: Denis Paperno

Abstract : Distributional semantic vectors (also known as word embeddings) are increasingly popular in various natural language tasks. The talk will describe how distributional semantic models are created, investigate some of the model hyperparameters, and illustrate their applications.


XMG2: Describing Description Languages    Posted:

Date : 01 December 2016, 11:00 am, Room B013

Speaker: Yannick Parmentier

Abstract : In this talk, we introduce XMG2, a modular and extensible tool for various linguistic description tasks. Based on the notion of meta-compilation (that is, compilation of compilers), XMG2 reuses the main concepts underlying XMG, namely logic programming and constraint satisfaction, to generate on-demand XMG-like compilers by assembling elementary units called language bricks. This brick-based definition of compilers permits users to design description languages in a highly flexible way. In particular, it makes it possible to support several levels of linguistic description (e.g. syntax, morphology) within a single description language. XMG2 aims to offer means for users to easily define description languages that fit as much as possible the linguistic intuition.


Is Very Deep Convolutional Neural Network necessary for Text Classification?    Posted:

Date : 01 December 2016, 10:00 am, Room B013

Speaker: Hoa Le Thien

Abstract : Convolutional Neural Network is famous for a long time on the Image Classification task because it can retrieve the state-of-the-art performance when it goes very deeply. It is demonstrated as well the same power for the domain of Speech Recognition but is it always the case for Text Classification ? There're a lot of results against this suspect. In this presentation, I will explain briefly the structure of a shallow Convolutional Neural Network and then compare its result with a Very Deep ConvNet. The others structures like word2vec, fasttext will also be included to discuss. The presentation will be concluded with a new perspective path of research.


Learning Embeddings to lexicalise RDF Properties    Posted:

Date : 10 November 2016, 10:30am, Room B013

Speaker: Laura Perez-Beltrachini

Abstract :
A difficult task when generating text from knowledge bases (KB) consists in finding appropriate lexicalisations for KB symbols. We present an approach for lexicalising knowledge base relations and apply it to DBPedia data. Our model learns low-dimensional embeddings of words and RDF resources and uses these representations to score RDF properties against candidate lexicalisations. Training our model using (i) pairs of RDF triples and automatically generated verbalisations of these triples and (ii) pairs of paraphrases extracted from various resources, yields competitive results on DBPedia data.


Sequence-based Structured Prediction for Semantic Parsing    Posted:

Date: 18 October, 2016, 14:00, Room A008

Speaker: Chunyang Xiao

Abstract : We propose an approach for semantic parsing that uses a recurrent neural network to map a natural language question into a logical form representation of a KB query. Building on recent work by (Wang et al., 2015), the interpretable logical forms, which are structured objects obeying certain constraints, are enumerated by an underlying grammar and are paired with their canonical realizations. In order to use sequence prediction, we need to sequentialize these logical forms.

We compare three sequentializations: a direct linearization of the logical form, a linearization of the associated canonical realization, and a sequence consisting of derivation steps relative to the underlying grammar. We also show how grammatical constraints on the derivation sequence can easily be integrated inside the RNN-based sequential predictor. Our experiments show important improvements over previous results for the same dataset, and also demonstrate the advantage of incorporating the grammatical constraints.


Exploiting Sentence and Context Representations in Deep Neural Models for Spoken Language Understanding    Posted:

Date: 28 September 2016, 14:00, Room C005

Speaker: Lina Rojas-Barahona

Abstract : This paper presents a deep learning architecture for the semantic decoder component of a Statistical Spoken Dialogue System. In a slot-filling dialogue, the semantic decoder predicts the dialogue act and a set of slot-value pairs from a set of n-best hypotheses returned by the Automatic Speech Recognition. Most current models for spoken language understanding assume (i) word-aligned semantic annotations as in sequence taggers and (ii) delexicalisation, or a mapping of input words to domain-specific concepts using heuristics that try to capture morphological variation but that do not scale to other domains nor to language variation (e.g., morphology, synonyms, paraphrasing ). In this work the semantic decoder is trained using unaligned semantic annotations and it uses distributed semantic representation learning to overcome the limitations of explicit delexicalisation. The proposed architecture uses a convolutional neural network for the sentence representation and a long-short term memory network for the context representation. Results are presented for the publicly available DSTC2 corpus and an In-car corpus which is similar to DSTC2 but has a significantly higher word error rate (WER).


Project GolFred Presentation    Posted:

Date: 16 September, 2016, 14:00, Room LORIA B-011

Speaker: Émilie Colin

Abstract : The project, golfred, is about machine reading for narrative generation of spatial experiences in service robots. A robot, Golem, reads the panels found while he moves in a real environment. The phrases read by golem are transformed by Fred into a semantic representation. Furthermore, this semantic representation is linked to and enriched with DBPedia knowledge. The task of the Synalp team is to develop a generator from the final representation produced by Fred. Those representations will contain any kind of event, role, specification. I worked on verbnet to generate a set of grammar trees linked to semantic schemas. I will present GenI, Verbnet, and their association and will close my presentation with the work on fred data.


Multimodal content-aware image thumbnailing    Posted:

Date: 22 September, 2016, 10:00, Room B-011

Speaker: Kohei Yamamoto

Abstract : In this presentation, I'd like to introduce my previous research topic, multimodal image thumbnailing. As a background, mobile applications (in this case, news article recommendation) have the key problem of needing to eliminate the redundant information in order to provide more relevant information within a limited time and space. To tackle this problem, I proposed a multimodal image thumbnailing method considering both images and text. The proposed method generates an energy map expressing content by aligning image fractions and words via multimodal neural networks, and we can crop an appropriate region with respect to the corresponding text by using the energy map. We evaluate this approach on a real data set based on news articles that appeared on Yahoo! JAPAN. Experimental results demonstrate the effectiveness of our proposed method.


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