Maya Ramanath

• Indian Institute of Technology Delhi

We introduce TechTrack, a new dataset for tracking entities in technical procedures. The dataset, prepared by annotating open domain articles from WikiHow, consists of 1351 procedures, e.g., "How to connect a printer", identifies more than 1200 unique entities with an average of 4.7 entities per procedure. We evaluate the performance of state-of-th...

While learning new technical material, a user faces difficulty encountering new concepts for which she does not have the necessary prerequisite knowledge. Determining the right set of prerequisites is challenging because it involves multiple searches on the web. Although a number of techniques have been proposed to retrieve prerequisites, none of t...

While learning new technical material, a user faces difficulty encountering new concepts for which she does not have the necessary prerequisite knowledge. Determining the right set of prerequisites is challenging because it involves multiple searches on the web. Although a number of techniques have been proposed to retrieve prerequisites, none of t...

Knowledge Graphs (KGs) extracted from text sources are often noisy and lead to poor performance in downstream application tasks such as KG-based question answering.While much of the recent activity is focused on addressing the sparsity of KGs by using embeddings for inferring new facts, the issue of cleaning up of noise in KGs through KG refinement...

Academic search engines allow scientists to explore related work relevant to a given query. Often, the user is also aware of the aspect to retrieve a relevant document. In such cases, existing search engines can be used by expanding the query with terms describing that aspect. However, this approach does not guarantee good results since plain keywo...

Academic search engines allow scientists to explore related work relevant to a given query. Often, the user is also aware of the "aspect" to retrieve a relevant document. In such cases, existing search engines can be used by expanding the query with terms describing that aspect. However, this approach does not guarantee good results since plain key...

Knowledge Graphs (KGs) are used to store heterogenous information in the form of graphs. One flexible and non-expert way to query these KGs is to use relationship queries or keyword search. The user can specify a query using keywords referring to entities in the graph. The system then returns a set of relationships among the queried entities. Howev...

Efficiently answering reachability queries on a directed graph is a fundamental problem and many solutions – theoretical and practical – have been proposed. A common strategy to make reachability query processing efficient, accurate and scalable is to precompute indexes on the graph. However this often becomes impractical, particularly when dealing...

Answering natural language questions posed on a knowledge graph requires traversing an appropriate sequence of relationships starting from the mentioned entities. To answer complex queries, we often need to traverse more than two relationships. Traditional approaches traverse at most two relationships, as well as typically first retrieve candidate...

In this paper, we make two main contributions. First, we describe the construction and evaluation of TeKnowbase, a knowledge-base of technical concepts in computer science. And second, we show how to use TeKnowbase in a variety of applications, including, generation of pre-requisite concepts for learning a new topic, classification of technical tex...

Graph structured data on the web is now massive as well as diverse, ranging from social networks, web graphs to knowledge-bases. Effectively querying this graph structured data is non-trivial. We are concerned with a class of queries called relationship queries, which are usually expressed as a set of keywords (each keyword denoting a named entity)...

Organisations store huge amounts of data from multiple heterogeneous sources in the form of Knowledge Graphs (KGs). One of the ways to query these KGs is to use SPARQL queries over a database engine. Since SPARQL follows exact match semantics, the queries may return too few or no results. Recent works have proposed query relaxation where the query...

Graph structured data on the web is now massive as well as diverse, ranging from social networks, web graphs to knowledge-bases. Effectively querying this graph structured data is non-trivial and has led to research in a variety of directions -- structured queries, keyword and natural language queries, automatic translation of these queries to stru...

In this paper, we address the problem of sampling from a set and reconstructing a set stored as a Bloom filter. To the best of our knowledge our work is the first to address this question. We introduce a novel hierarchical data structure called BloomSampleTree that helps us design efficient algorithms to extract an almost uniform sample from the se...

In this paper, we describe the construction of TeKnowbase, a knowledge-base of technical concepts in computer science. Our main information sources are technical websites such as Webopedia and Techtarget as well as Wikipedia and online textbooks. We divide the knowledge-base construction problem into two parts -- the acquisition of entities and the...

Knowledge graphs (KGs) are important assets for search, analytics, and recommendations. However, querying a KG to explore entities and discover facts is difficult and tedious, even for users with skills in SPARQL. First, users are not familiar with the structure and labels of entities, classes and relations. Second, KGs are bound to be incomplete,...

We propose a demonstration of our system, OpinioNetIt, a structured, faceted, knowledge-base of opinions, and its use in political analysis. OpinioNetIt consists of information about people, topics and opinions in the form of triples, indicating the opinion of a person on a topic. Our focus is on acquiring opinions held by various stakeholders on p...

This paper describes OpinioNetIt, a structured, faceted, knowledge-base of opinions, and its use in political opinions analysis. OpinioNetIt consists of information about people, topics and opinions in the form of person, opinion, topic triples, indicating the opinion of a person on a topic. Our specific focus has been on acquiring opinions held by...

We consider the problem of automatically classifying quotations about political debates into both topic and polarity. These quotations typically appear in news media and online forums. Our approach maps quotations onto one or more topics in a category system of political debates, containing more than a thousand fine-grained topics. To overcome the...

We demonstrate RDF Xpress, a search engine that enables users to effectively retrieve information from large RDF knowledge bases or Linked Data Sources. RDF Xpress provides a search interface where users can combine triple patterns with keywords to form queries. Moreover, RDF Xpress supports automatic query relaxation and returns a ranked list of d...

The Linked Data initiative comprises struc-tured databases in the Semantic-Web data model RDF. Exploring this heterogeneous data by structured query languages is tedious and error-prone even for skilled users. To ease the task, this paper presents a methodology for translating natural language questions into structured SPARQL queries over linked-da...

We present DEANNA, a framework for natural language question answering over structured knowledge bases. Given a natural language question, DEANNA translates questions into a structured SPARQL query that can be evaluated over knowledge bases such as Yago, Dbpedia, Freebase, or other Linked Data sources. DEANNA analyzes questions and maps verbal phra...

The wikileaks documents about the death of Osama Bin Laden and the debates about the economic crisis in Greece and other European countries are some of the controversial topics being played on the news everyday. Each of these topics has many different aspects, and there is no absolute, simple truth in answering questions such as: should the EU guar...

The wikileaks documents or the economic crises in Ireland and Portugal are some of the controversial topics being played on the news everyday. Each of these topics has many different aspects, and there is no absolute, simple truth in answering questions such as: should the EU guarantee the financial stability of each member country, or should the c...

Entity-relationship-structured data is becoming more important on the Web. For example, large knowledge bases have been automatically constructed by information extraction from Wikipedia and other Web sources. Entities and relationships can be represented by subject-property-object triples in the RDF model, and can then be precisely searched by str...

Large knowledge bases, the Linked Data cloud, and Web 2.0 communities open up new opportunities for deep question answering to support the advanced information needs of knowledge workers like students, journalists, or business analysts. This calls for going beyond keyword search, towards more expressive ways of entity-relationship-oriented querying...

Given a controversial political topic, our aim is to classify documents debating the topic into pro or con. Our approach extracts topic related terms, pro/con related terms, and pairs of topic related and pro/con related terms and uses them as the basis for constructing a pro query and a con query. Following standard LM techniques, a document is cl...

The proliferation of knowledge-sharing communities like Wikipedia and the advances in automated information extraction from Web pages enable the construction of large knowledge bases with facts about entities and their relationships. The facts can be represented in the RDF data model, as so-called subject-property-object triples, and can thus be qu...

The success of knowledge-sharing communities like Wikipedia and the advances in automatic information extraction from textual and Web sources have made it possibleto build large "knowledge repos- itories" such as DBpedia, Freebase, and YAGO. These collections can be viewed as graphs of entities and relationships (ER graphs) and can be represented a...

XML has become the de-facto standard for data representation and exchange, resulting in large scale repositories and warehouses of XML data. In order for users to understand and explore these large collections, a summarized, bird's eye view of the available data is a necessity. In this paper, we are interested in semantic XML document summaries whi...

We present ANGIE, a system that can answer user queries by com- bining knowledge from a local database with knowledge retrieved from Web services. If a user poses a query that cannot be answered by the local database alone, ANGIE calls the appropriate Web ser- vices to retrieve the missing information. This information is inte- grated seamlessly an...

We propose a language-model-based ranking approach for SPARQL- like queries on entity-relationship graphs. Our ranking model sup- ports exact matching, approximate structure matching, and approx- imate matching with text predicates. We show the effectiveness of our model through examples.

Our aim here is to advocate for the integration of database-systems (DB) methods and information-retrieval (IR) methods to address applications that are emerging from the ongoing explosion and diversification of digital information. One grand goal of such an endeavor is the automatic building and maintenance of a comprehensive knowledge base of fac...

Suppose there is a large corpus of XML documents, each of which describes a movie released in the last 30 years (for example, extracted from IMDB). A movie enthusiast wants to make a list of interesting movies based on various crite- ria, such as, the genre, lead actors, directors, etc. She rst decides to narrow the focus to just thrillers. However...

Large graphs and networks are abundant in modern information systems: entity-relationship graphs over relational data or Web-extracted entities, biological networks, social online communities, knowledge bases, and many more. Often such data comes with expressive node and edge labels that allow an interpretation as a semantic graph, and edge weights...

This paper gives an overview on the YAGO-NAGA ap- proach to information extraction for building a conve- niently searchable, large-scale, highly accurate knowl- edge base of common facts. YAGO harvests infoboxes and category names of Wikipedia for facts about indi- vidual entities, and it reconciles these with the taxo- nomic backbone of WordNet in...

The presence of encyclopedic Web sources, such as Wikipedia, the Internet Movie Database (IMDB), World Factbook, etc. calls for new querying techniques that are simple and yet more expressive than those provided by standard keyword-based search engines. Searching for explicit knowledge needs to consider inherent semantic structures involving entiti...

With XML becoming a standard for data representation and exchange, we can expect to see large scale repositories and warehouses of XML data. In order for users to understand and explore these large collections, a summarized, bird's eye view of the available data is a necessity. In this paper, we are interested in semantic XML document summaries whi...

The Web has the potential to become the world's largest knowledge base. In order to unleash this potential, the wealth of information available on the Web needs to be extracted and organized. There is a need for new querying techniques that are simple and yet more expressive than those provided by standard keyword-based search engines. Searching fo...

Current keyword-oriented search engines for the World Wide Web do not allow specifying the semantics of queries. We address this limitation with NAGA1, a new semantic search engine. NAGA builds on a large semantic knowledge base of binary relationships (facts) derived from the Web. NAGA provides a simple, yet expressive query language to query this...

Current approaches for estimating the cardinality of XML queries are applicable to a static scenario wherein the underlying XML data does not change subsequent to the collection of statistics on the repository. However, in practice, many XML-based applications are dynamic and involve frequent updates to the data. In this paper, we investigate effic...

A key component of XML data management systems is the result size estimator, which estimates the cardinalities of user queries. Estimated cardinalities are needed in a variety of tasks, including query optimization and cost-based storage design; and they can also be used to give users early feedback about the expected outcome of their queries. In c...

We consider the problem of cost-based strategies to derive efficient relational configurations for XML applications that subscribe to an XML Schema. In particular, we propose a flexible framework for XML schema transformations and show how it can be used to design algorithms to search the space of equivalent relational configurations. We study the...

We present LegoDB, a cost-based XML storage mapping engine that automatically explores a space of possible XML-to-relational mappings and selects an efficient mapping for a given application.

We present LegoDB, a cost-based XML storage mappingengine that automatically explores a space of possibleXML-to-relational mappings and selects an efficient mappingfor a given application.

eXtensible Markup Language (XML) is becoming the predominant data exchange format in a variety of application domains (supply-chain, scientific data processing, telecommunication infrastructure, etc.). Not only is an increasing amount of XML data now being processed, but XML is also increasingly being used in business-critical applications. Efficie...

Introduction XML is becoming the predominant data exchange format in a variety of application domains (supply-chain, scientific data processing, telecommunication infrastructure, etc.). Not only is an increasing amount of XML data now being processed, but XML is also increasingly being used in business-critical applications. Efficient and reliable...

The availability of summary data for XML documents has many applications, from providing users with quick feedback about their queries, to cost-based storage design and query optimization. StatiX is a novel XML Schema-aware statistics framework that exploits the structure derived by regular expressions (which define elements in an XML Schema) to pi...

Not Available

Current proposals for web querying systems have assumed a centralized processing architecture wherein data is shipped from the remote sites to the user's site. We present here the design and implementation of DIASPORA, a highly distributed query processing system for the web. It is based on the premise that several web applications are more natural...

Ammonium perchlorate (AP) has been coated with polystyrene (PS), cellulose acetate (CA), Novolak resin and polymethylmethacrylate (PMMA) by a solvent/nonsolvent method which makes use of the coacervation principle. The effect of polymer coating on AP decomposition has been studied using thermogravimetry (TG) and differential thermal analysis (DTA)....

Thermal decomposition and combustion of lithium perchlorate ammine:ammonium perchlorate (LPA:AP) and magnesium perchlorate ammine:ammonium perchlorate (MPA:AP) pellets have been studied using DTA, TG, and strand burner techniques. The DTA results of the ammine:AP pellets show that the addition of ammines lowers the ignition temperature of AP. Howev...

Addition of trimethylammonium perchlorate to potassium perchlorate (KP) catalyzes its thermal decomposition. However, although the additive sensitises KP-PU propellant decomposition, its combustion is desensitised. The observed effects have been explained in terms of the role played by the early formation of potassium chloride.

This article advocates that database-systems (DB) and infor-mation-retrieval (IR) methods be integrated to address the needs of important applications that emerge with the on-going explosion and diversification of digital information. A grand challenge that a joint DB&IR endeavor could aim for is to automatically build and maintain a comprehensive...

Cost-based strategies to derive relational configurations for XML applications have been recently proposed and shown to provide substantially better configura- tions than heuristic methods. These strategies make use of schema transformations to a canonical schema in order to derive various relational configurations. In this paper, we propose a flex...

Recent work on building semantic search engines has given rise to large graph-based knowledge repositories and facil- ities for querying them and more importantly, ranking the results. While the ranking provided may prove to be accept- able in general, for a truly satisfactory search experience, it is necessary to tailor the results according to th...