Grammars & Parsing
Synthesis of Programs from Multimodal Datasets
Thakoor, Shantanu (Stanford University) | Shah, Simoni (Indian Institute of Technology, Bombay) | Ramakrishnan, Ganesh (Indian Institute of Technology, Bombay) | Sanyal, Amitabha (Indian Institute of Technology, Bombay)
We describe MultiSynth, a framework for synthesizing domain-specific programs from a multimodal dataset of examples. Given a domain-specific language (DSL), a dataset is multimodal if there is no single program in the DSL that generalizes over all the examples. Further, even if the examples in the dataset were generalized in terms of a set of programs, the domains of these programs may not be disjoint, thereby leading to ambiguity in synthesis. MultiSynth is a framework that incorporates concepts of synthesizing programs with minimum generality, while addressing the need of accurate prediction. We show how these can be achieved through (i) transformation driven partitioning of the dataset, (ii) least general generalization, for a generalized specification of the input and the output, and (iii) learning to rank, for estimating feature weights in order to map an input to the most appropriate mode in case of ambiguity. We show the effectiveness of our framework in two domains: in the first case, we extend an existing approach for synthesizing programs for XML tree transformations to ambiguous multimodal datasets. In the second case, MultiSynth is used to preorder words for machine translation, by learning permutations of productions in the parse trees of the source side sentences. Our evaluations reflect the effectiveness of our approach.
Learning Structured Text Representations
In this paper, we focus on learning structure-aware document representations from data without recourse to a discourse parser or additional annotations. Drawing inspiration from recent efforts to empower neural networks with a structural bias (Cheng et al., 2016; Kim et al., 2017), we propose a model that can encode a document while automatically inducing rich structural dependencies. Specifically, we embed a differentiable non-projective parsing algorithm into a neural model and use attention mechanisms to incorporate the structural biases. Experimental evaluations across different tasks and datasets show that the proposed model achieves state-of-the-art results on document modeling tasks while inducing intermediate structures which are both interpretable and meaningful.
Natural Language Multitasking: Analyzing and Improving Syntactic Saliency of Hidden Representations
Brunner, Gino, Wang, Yuyi, Wattenhofer, Roger, Weigelt, Michael
We train multi-task autoencoders on linguistic tasks and analyze the learned hidden sentence representations. The representations change significantly when translation and part-of-speech decoders are added. The more decoders a model employs, the better it clusters sentences according to their syntactic similarity, as the representation space becomes less entangled. We explore the structure of the representation space by interpolating between sentences, which yields interesting pseudo-English sentences, many of which have recognizable syntactic structure. Lastly, we point out an interesting property of our models: The difference-vector between two sentences can be added to change a third sentence with similar features in a meaningful way.
57 Summaries of Machine Learning and NLP Research - Marek Rei
Staying on top of recent work is an important part of being a good researcher, but this can be quite difficult. Thousands of new papers are published every year at the main ML and NLP conferences, not to mention all the specialised workshops and everything that shows up on ArXiv. Going through all of them, even just to find the papers that you want to read in more depth, can be very time-consuming. In this post, I have summarised 50 papers. After going through a paper, if I had the chance, I would write down a few notes and summarise the work in a couple of sentences. These are not meant as reviews – I'm not commenting on whether I think the paper is good or not. But I do try to present the crux of the paper as bluntly as possible, without unnecessary sales tactics. Hopefully this can give you the general idea of 50 papers, in roughly 20 minutes of reading time. The papers are not selected or ordered based on any criteria. It is not a list of the best papers I have read, more like a random sample.
Relationship between Natural Language Processing and AI
Modeling various aspects of language--syntax, semantics, pragmatics, and discourse, among others--by the use of constrained formal-computational systems, just adequate for such modeling, has proved to be an effective research strategy, leading to deep understanding of these aspects, with implications for both machine processing and human processing. This approach enables one to distinguish between the universal and stipulative constraints.
Statistical Techniques for Natural Language Parsing
I review current statistical work on syntactic parsing and then consider part-of-speech tagging, which was the first syntactic problem to successfully be attacked by statistical techniques and also serves as a good warm-up for the main topic--statistical parsing. Here, I consider both the simplified case in which the input string is viewed as a string of parts of speech and the more interesting case in which the parser is guided by statistical information about the particular words in the sentence. Finally, I anticipate future research directions. In this example, I adopt the standard abbreviations: s for sentence, np for noun phrase, vp for verb phrase, and det for determiner. It is generally accepted that finding the sort of structure shown in figure 1 is useful in determining the meaning of a sentence.
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This report is a review of the First National Conference on Knowledge Representation and Inference in Sanskrit, Bangalore, India, 20 through 22 December, 1986 The conference was inspired by an article that appeared in the Spring 1985 issue of AI Magazine--"Knowledge Representation in Sanskrit and Artificial Intelligence." A working group has been created to pursue the goals of the conference and to possibly arrange another conference for 1987 and 1988 This conference is analogous to the consultation of philosophers and cognitive psychologists by computer scientists in the beginnings of AI. Western psychology and philosophy is quite different from the Indo-Aryan tradition: the former has its basis in Aristotelian logic and the scientific method, whereas the latter is also based on introspection and internal experience Nevertheless, both these schools have converged in the analysis of natural language and the extraction of the semantic message from a text.The purpose of AI in this context is to derive a "method" for natural language understanding; the purpose for the Sanskrit scholars was to understand the nature of language and thought in and of itself. Hence, for the Sanskrit scholars, the actual methodology was implicit; it was not the focus. The purpose of the conference was to extract this hidden "algorithm" of automatic semantic parsing from the Sanskrit pandits.
Knowledge Representation in Sanskrit and Artificial Intelligence
In the past twenty years, much time, effort, and money has been expended on designing an unambiguous representation of natural languages to make them accessible to computer processing These efforts have centered around creating schemata designed to parallel logical relations with relations expressed by the syntax and semantics of natural languages, which are clearly cumbersome and ambiguous in their function as vehicles for the transmission of logical data. Understandably, there is a widespread belief that natural languages arc unsuitable for the transmission of many ideas that artificial languages can render with great precision and mathematical rigor. But this dichotomy, which has served as a premise underlying much work in the areas of linguistics and artificial intelligence, is a false one There is at least one language, Sanskrit, which for the duration of almost 1000 years was a living spoken language with a considerable literature of its own Besides works of literary value, there was a long philosophical and grammatical tradition that has continued to exist with undiminished vigor until the present century. Among the accomplishments of the grammarians can be reckoned a method for paraphrasing Sanskrit in a manner that is identical not only in essence but in form with current work in Artificial Intelligence This article demonstrates that a natural language can serve as an artificial language also, and that much work in AI has been reinventing a wheel millenia old First, a typical Knowledge Representation Scheme (using Semantic Nets) will be laid out, followed by an outline of the method used by the ancient Indian Grammarians to analyze sentences unambiguously. Finally, the clear parallelism between the two will be demonstrated, and the theoretical implications of this equivalence will be given.
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The other articles in the NL chapter of the Handbook include a historical sketch of machine translation from one language to another, which was the subject of the very earliest ideas about processing language with computers; technical articles on some of the grammars and parsing techniques that AI researchers have used in their programs; and an article on text generation, the creation of sentences by the program. Finally, there are several articles describing the NL programs themselves: the early systems of the 1960s and the major research projects of the last decade, including Wilks'S machine translation system, Winograd's SHRDLU, Woods's LUNAR, Schank's MARGIE, SAM, and PAM, and Hendrix's LIFER. Two other chapters of the Handbook are especially relevant to NL research. Speech understanding research attempts to build computer interfaces that understand spoken language. In the 197Os, speech and natural language understanding research were often closely linked.
John C. Glasgow I1
An important issue in achieving acceptance of computer systems used by the nonprogramming community is the ability to communicate with these systems in natural language. Often, a great deal of time in the design of any such system is devoted to the natural language front end. An obvious way to simplify this task is to provide a portable natural language front-end tool or facility that is sophisticated enough to allow for a reasonable variety of input; allows modification; and, yet, is easy to use. This paper describes such a tool that is based on augmented transition networks (ATNs). It allows for user input to be in sentence or nonsentence form or both, provides a detailed parse tree that the user can access, and also provides the facility to generate responses and save information.