Abstract

The recent large scale advances in science and technology has resulted in accumulation of large amount of biological pathways data. Any metabolic pathway contains large number of enzymes, metabolites and reactions. To make sense of diverse data available on a system, one needs to correlate and analyze them as a whole. Motivated by the potential benefits of graph theory and its application in biological data, we discuss the automated reconstruction and analysis of metabolite network of Arabidopsis thaliana using concepts of graph theory. A.thaliana metabolite network was reconstructed and analysis of the global properties of its metabolite-centric graph shows that the network is small-world and scale-free in nature. The investigation of nodes with high centrality values like high degree and high betweeness in this network help in identifying important metabolites, reactions, etc. Newman’s modularity-based approach has been used in the analysis of the metabolite network of A. thaliana to identify pathway clusters, isolated pathways, and orphan metabolites or products. Our analysis on network representations helps in understanding the relationship between the metabolites, enzymes and reactions of metabolic pathways in A. thaliana.

Abstract

In this paper we analyze the topological properties of airport network of India (ANI) using graph theoretic approach. We show that such an analysis can be useful not only in planning the infrastructure and growth of the air-traffic connectivity, but also in managing the flow of transportation during emergencies such as accidental failure of the airport, close down of the airport due to unexpected climate changes, terrorist attacks, etc. Knowledge of the connectivity pattern and load on various routes can also help in making judicious decisions for reduction of flights to contain the spread of the infectious disease.

Abstract

Measuring inter-document similarity is one of the most essential steps in text document clustering. Traditional methods rely on representing text documents using the simple Bag-of-Words (BOW) model which assumes that terms of a text document are independent of each other. Such single term analysis of the text completely ignores the underlying (semantic) structure of a document. In the literature, sufficient efforts have been made to enrich BOW representation using phrases and n-grams like bi-grams and tri-grams. These approaches take into account dependency only between adjacent terms or a continuous sequence of terms. However, while some of the dependencies exist between adjacent words, others are more distant. In this paper, we make an effort to enrich traditional document vector by adding the notion of term-pair features. A Term-Pair feature is a pair of two terms of the same document such that they may be adjacent to each other or distant. We investigate the process of term-pair selection and propose a methodology to select potential term-pairs fromthe given document. Utilizing term proximity between distant terms also allows some flexibility for two documents to be similar if they are about similar topics but with varied writing styles. Experimental results on standard web document data set show that the clustering performance is substantially improved by adding term-pair features.

Abstract

In this paper we introduce a novel and efficient approach to detect and rank topics in a large corpus of research papers. With rapidly growing size of academic literature, the problem of topic detection and topic ranking has become a challenging task. We present a unique approach that uses closed frequent keyword-set to form topics. We devise a modified time independent Page Rank algorithm that assigns an authoritative score to each topic by considering the sub-graph in which the topic appears, producing a ranked list of topics.The use of citation network and the introduction of time in variance in the topic ranking algorithm reveal very interesting results. Our approach also provides a clustering technique for the research papers using topics as similarity measure. We extend our algorithms to study various aspects of topic evolution which gives interesting insight into trends in research areas over time.Our algorithms also detect hot topics and landmark topics over the years. We test our algorithms on the DBLP dataset and show that our algorithms are fast, effective and scalable.

Abstract

In this paper we introduce a novel and efficient approach to detect topics in a large corpus of research papers. With rapidly growing size of academic literature, the problem of topic detection has become a very challenging task. We present a unique approach that uses closed frequent keyword-set to form topics. Our approach also provides a natural method to cluster the research papers into hierarchical, overlapping clusters using topic as similarity measure. To rank the research papers in the topic cluster, we devise a modified PageRank algorithm that assigns an authoritative score to each research paper by considering the sub-graph in which the research paper appears. We test our algorithms on the DBLP dataset and experimentally show that our algorithms are fast, effective and scalable.

Abstract

In this paper we propose an efficient method to rank the research papers from various fields of research published in various conferences over the years. This ranking method is based on citation network. The importance of a research paper is captured well by the peer vote, which in this case is the research paper being cited in other research papers. Using a modified version of the PageRank algorithm, we rank the research papers, assigning each of them an authoritative score. Using the scores of the research papers calculated by above mentioned method, we formulate scores for conferences and authors and rank them as well. We have introduced a new metric in the algorithm which takes into account the time factor in ranking the research papers to reduce the bias against the recent papers which get less time for being studied and consequently cited by the researchers as compared to the older papers. Often a researcher is more interested in finding the top conferences in a particular year rather than the overall conference ranking. Considering the year of publication of the papers, in addition to the paper scores we also calculated the year-wise score of each conference by slight improvisation of the above mentioned algorithm.

Abstract

The concept of similarity is fundamentally important in al-most every scientific field. Clustering, distance-based outlier detection,classification, regression and search are major data mining techniques which compute the similarities between instances and hence the choice of a particular similarity measure can turn out to be a major cause of success or failure of the algorithm. The notion of similarity or distance for categorical data is not as straightforward as for continuous data and hence, is a major challenge. This is due to the fact that different values taken by a categorical attribute are not inherently ordered and hence anotion of direct comparison between two categorical values is not pos-sible. In addition, the notion of similarity can differ depending on the particular domain, dataset, or task at hand. In this paper we present anew similarity measure for categorical data DISC - Data-Intensive Simi-larity Measure for Categorical Data. DISC captures the semantics of the data without any help from domain expert for defining the similarity. In addition to these, it is generic and simple to implement. These desirable features make it a very attractive alternative to existing approaches. Our experimental study compares it with 14 other similarity measures on 24standard real datasets, out of which 12 are used for classification and 12for regression, and shows that it is more accurate than all its competitors.

Abstract

Online advertising offers significantly finer granularity, which has been leveraged in state-of-the-art targeting methods, like Behavioral Targeting (BT). Such methods have been fur-ther complemented by recent work in Look-alike Modeling(LAM) which helps in creating models which are customized according to each advertiser’s requirements and each cam-paign’s characteristics, and which show ads to users who are most likely to convert on them, not just click them. In Look-a like Modeling given data about converters and non-converters, obtained from advertisers, we would like to train models automatically for each ad campaign. Such custom models would help target more users who are similar to the set of converters the advertiser provides. The advertisers get more freedom to define their preferred sets of users which should be used as a basis to build custom targeting models.In behavioral data, the number of conversions (positive class) per campaign is very small (conversions per impression for the advertisers in our data set are much less than 10−4),giving rise to a highly skewed training dataset, which has most records pertaining to the negative class. Campaigns with very few conversions are called as tail campaigns, and those with many conversions are called head campaigns.Creation of Look-alike Models for tail campaigns is very challenging and tricky using popular classifiers like Linear SVM and GBDT, because of the very few number of posi-tive class examples such campaigns contain. In this paper,we present an Associative Classification (AC) approach to LAM for tail campaigns. Pairs of features are used to deriverules to build a Rule-based Associative Classifier, with the rules being sorted by frequency-weighted log-likelihood ratio(F-LLR). The top krules, sorted by F-LLR, are then applied to any test record to score it. Individual features can also form rules by themselves, though the number of such rules in the top krules and the whole rule-set is very small. Our algorithm is based on Hadoop, and is thus very efficient in terms of speed.

Abstract

Associative Classification leverages Association Rule Min-ing (ARM) to train Rule-based classifiers. The classifiers are built on high quality Association Rules mined from the given dataset. Associative Classifiers are very accurate be-cause Association Rules encapsulate all the dominant and statistically significant relationships between items in the dataset. They are also very robust as noise in the form of insignificant and low-frequency itemsets are eliminated dur-ing the mining and training stages. Moreover, the rules are easy-to-comprehend, thus making the classifier transparent.Conventional Associative Classification and Association Rule Mining (ARM) algorithms are inherently designed to work only with binary attributes, and expect any quantita-tive attributes to be converted to binary ones using ranges,like “Age = [25, 60]”. In order to mitigate this constraint,Fuzzy logic is used to convert quantitative attributes to fuzzy binary attributes, like “Age = Middle-aged”, so as to elimi-nate any loss of information arising due to sharp partition-ing, especially at partition boundaries, and then generate Fuzzy Association Rules using an appropriate Fuzzy ARM algorithm. These Fuzzy Association Rules can then be used to train a Fuzzy Associative Classifier. In this paper, we also show how Fuzzy Associative Classifiers so built can be used in a wide variety of domains and datasets, like transactional datasets and image datasets.

Abstract

We use text mining mechanisms to analyze Hot days in news feeds. We build upon the earlier work used to detect Hot topics and assume that we have already attained the Hot days. In this paper we identify the most relevant documents of a topic on a Hot day. We construct a similarity based technique for identifying and ranking these documents. Our aim is to automatically detect chains of hot correlated events over time.We develop a scheme using similarity measures like cosine similarity and KL-divergence to find correlation between these Hot days. For the ‘U.S. Presidential Elections’, the presidential debates which spanned over a week was one such event.