We present a new approach to reasoning about the outcome of an argumentation framework, where an agent's reasoning with a framework and semantics is represented by an inference relation defined over a logical labeling language. We first study a monotonic type of inference which is, in a sense, more general than an acceptance function, but equally expressive. In order to overcome the limitations of this expressiveness, we study a non-monotonic type of inference which allows counterfactual inferences. We precisely characterize the classes of frameworks distinguishable by the non-monotonic inference relation for the admissible semantics.

We study and propose in this article several novel solutions to the task of semantic similarity between two short texts. The proposed solutions are based on the probabilistic method of Latent Dirichlet Allocation (LDA) and on the algebraic method of Latent Semantic Analysis (LSA). Both methods, LDA and LSA, are completely automated methods used to discover latent topics or concepts from large collection of documents. We propose a novel word-to-word similarity measure based on LDA as well as several text-to-text similarity measures. We compare these measures with similar, known measures based on LSA. Experiments and results are presented on two data sets: the Microsoft Research Paraphrase corpus and the User Language Paraphrase corpus. We found that the novel word-to-word similarity measure based on LDA is extremely promising.

This study expands upon an existing model of students’ reading comprehension ability within an intelligent tutoring system. The current system evaluates students’ natural language input using a local student model. We examine the potential to expand this model by assessing the linguistic features of self-explanations aggregated across entire passages. We assessed the relationship between 126 students’ reading comprehension ability and the cohesion of their aggregated self-explanations with three linguistic features. Results indicated that the three cohesion indices accounted for variance in reading ability over and above the features used in the current algorithm. These results demonstrate that broadening the window of NLP analyses can strengthen student models within ITSs.

This study compares automated scoring increases and linguistic changes for student writers in two groups: a group that used an intelligent tutoring system embedded with an automated writing evaluation component (Writing Pal) and a group that used only the automated writing evaluation component. The primary goal is to examine automated scoring differences in both groups from pretest to posttest essays to investigate score gains and linguistic development. The study finds that both groups show significant increases in automated writing scores and significant development in lexical, syntactic, cohesion, and rhetorical features. However, the Writing-Pal group shows greater raw frequency gains (i.e., negative v. positive gains).

In this paper we incorporate integrity constraints in Dung-style abstract argumentation frameworks. We show that even for constraints of a very simple form standard conflict-free semantics for argumentation frameworks are not adequate, as conflicts among arguments should sometimes be accepted and tolerated. For this, we use conflict-tolerant semantics and show how corresponding extensions may be represented in terms of propositional formulas.

We propose and develop a simple and efficient algorithm for generating extractive multi-document summaries and show that this algorithm exhibits state-of-the-art or near state-of-the-art performance on two Document Understanding Conference datasets and two Text Analysis Conference datasets. Our results show that algorithms using simple features and computationally efficient methods are competitive with much more complex methods for multi-document summarization (MDS). Given these findings, we believe that our summarization algorithm can be used as a baseline in future MDS evaluations. Further, evidence shows that our system is near the upper limit of performance for extractive MDS.

While researching spatial movements in play-scripts, we uncovered some movements that actors performed that could not be explained by the annotations or basic theatre rules. Here, we look to learn implied motion based on what the characters in the play are saying. Humans are able to do this with only being given the play-script, so how do we get a computer to do it? Several features, including n -grams, parts of speech (POS) bag of words (BoW), length of speech, and other contextual details were utilized with several machine learning methods to help predict movement within the play. Results reveal that is a difficult problem and basic natural language processing (NLP) and machine learning (ML) techniques do not perform much better than a random classifier.

In this paper we experiment with supervised machine learning techniques for the task of assigning semantic categories to nouns in Czech. The experiments work with 16 semantic categories based on available manually annotated data. The paper compares two possible approaches - one based on the contextual information, the other based upon morphological properties - we are trying to automatically extract final segments of lemmas which might carry semantic information. The central problem of this research is finding the features for machine learning that produce better results for relatively small training data size.

Information retrieval applications are essential tools to manage the huge amount of information in the Web. Ontologies have great importance in these applications. The idea here is that several data belonging to a domain of interest are represented and related semantically in the ontology, which can help to navigate, manage and reuse these data. Despite of the growing need of ontology, only few works were interested in Arabic language. Indeed, arabic texts are highly ambiguous, especially when diacritics are absent. Besides, existent works does not cover all the types of semantic relations, which are useful to structure Arabic ontologies. A lot of work has been done on cooccurrence- based techniques, which lead to over-generation. In this paper, we propose a new approach for Arabic semantic relation extraction. We use vocalized texts to reduce ambiguities and propose a new distributional approach for similarity calculus, which is compared to cooccurrence. We discuss our contribution through experimental results and propose some perspectives for future research.

.Introduction to the papers presented at the 2013 FLAIRS Conference Special Track on Applied Natural Language Processing.