Tarique Anwar

Mining feature-opinion pairs and their reliability scores from web opinion sources

Due to proliferation of Web 2.0, there is an exponential growth in user generated contents in the form of customer reviews on the Web, containing precious information useful for both customers and manufacturers. However, most of the contents are stored in either unstructured or semi-structured format due to which distillation of knowledge from this huge repository is a challenging task. In this paper, we propose a text mining approach to mine product features, opinions and their reliability scores from Web opinion sources. A rule-based system is implemented, which applies linguistic and semantic analysis of texts to mine feature-opinion pairs that have sentence-level co-occurrence in review documents. The extracted feature-opinion pairs and source documents are modeled using a bipartite graph structure. Considering feature-opinion pairs as hubs and source documents as authorities, Hyperlink-Induced Topic Search (HITS) algorithm is applied to generate reliability score for each feature-opinion pair with respect to the underlying corpus. The efficacy of the proposed system is established through experimentation over customer reviews on different models of electronic products.

Identifying cliques in dark web forums - An agglomerative clustering approach

In this paper, we present a novel agglomerative clustering method to identify cliques in dark Web forums. Considering each post as an individual entity accompanying all the information about its thread, author, time-stamp, etc., we have defined a similarity function to identify similarity between each pair of posts as a blend of their contextual and temporal coherence. The similarity function is employed in the proposed clustering algorithm to group threads into different clusters that are finally presented as individual cliques. The identified cliques are characterized using the homogeneity of posts therein, which also establishes the homogeneity of their authors and threads as well.

Partitioning road networks using density peak graphs

Road traffic networks are rapidly growing in size with increasing complexities. To simplify their analysis in order to maintain smooth traffic, a large urban road network can be considered as a set of small sub-networks, which exhibit distinctive traffic flow patterns. In this paper, we propose a robust framework for spatial partitioning of large urban road networks based on traffic measures. For a given urban road network, we aim to identify the different sub-networks or partitions that exhibit homogeneous traffic patterns internally, but heterogeneous patterns to others externally. To this end, we develop a two-stage algorithm (referred as FaDSPa) within our framework. It first transforms the large road graph into a well-structured and condensed density peak graph (DPG) via density based clustering and link aggregation using traffic density and adjacency connectivity, respectively. Thereafter we apply our spectral theory based graph cut (referred as α-Cut) to partition the DPG and obtain the different sub-networks. Thus the framework applies the locally distributed computations of density based clustering to improve efficiency and the centralized global computations of spectral clustering to improve accuracy. We perform extensive experiments on real as well as synthetic datasets, and compare its performance with that of an existing road network partitioning method. Our results show that the proposed method outperforms the existing normalized cut based method for small road networks and provides impressive results for much larger networks, where other methods may face serious problems of time and space complexities. HighlightsAn effective as well as efficient road network partitioning framework using both density and spectral based clustering.A fast density-based road network partitioning method FaDPa (extended to FaDPa+) is developed.Using FaDPa, a spectral based method FaDSPa is developed for partitioning small as well as large road networks.The complete derivation to optimize the α -Cut objective function (proposed in Anwar et al., EDBT 2014) is presented.Extensive experiments are conducted on real as well as synthetic datasets.

Spatial partitioning of large urban road networks

The rapid global migration of people towards urban areas is multiplying the traffic volume on urban road networks. As a result these networks are rapidly growing in size, in which different sub-networks exhibit distinctive traffic flow patterns. In this paper, we propose a scalable framework for traffic congestion-based spatial partitioning of large urban road networks. It aims to identify different sub-networks or partitions that exhibit homogeneous traffic congestion patterns internally, but heterogenous to others externally. To this end, we develop a two-stage procedure within our framework that first transforms the large road graph into a well-structured and condensed supergraph via clustering and link aggregation based on traffic density and adjacency connectivity, respectively. We then devise a spectral theory based novel graph cut (referred as -Cut) to partition the supergraph and compare its performance with that of an existing method for partitioning urban networks. Our results show that the proposed method outperforms the normalized cut based existing method in all the performance evaluation metrics for small road networks and provides good results for much larger networks where other methods may face serious problems of time and space complexities.

Web content mining for alias identification: A first step towards suspect tracking

In this paper, we present the design of a web content mining system to identify and extract aliases of a given entity from the Web in an automatic way. Starting with a pattern-based information extraction process, the system applies n-gram technique to extract candidate aliases. Thereafter, various statistical measures are applied to identify feasible aliases from them. The extracted aliases can be used to generate profiles of suspects and keep track of their movements on the Web using different identities.

An MCL-Based Text Mining Approach for Namesake Disambiguation on the Web

In this paper, we propose a Markov Clustering (MCL) based text mining approach for namesake disambiguation on the Web. The novelty of the proposed technique lies in modeling the collection of web pages using a weighted graph structure and applying MCL to crystalize it into different clusters, each one containing the web pages related to a particular namesake individual. The proposed method focuses on three broad and realistic aspects to cluster web pages retrieved through search engines - content overlapping, structure overlapping, and local context overlapping. The efficacy of the proposed method is demonstrated through experimental evaluations on standard datasets.

A web content mining approach for tag cloud generation

Tag cloud, also known as word cloud, are very useful for quickly perceiving the most prominent terms embedded within a text collection to determine their relative prominence. The effectiveness of tag clouds to conceptualize a text corpus is directly proportional to the quality of the keyphrases extracted from the corpus. Although, authors provide a list of about five to ten keywords in scientific publications that are used to map them into their respective domain, due to exponential growth in non-scientific documents on the World Wide Web, an automatic mechanism is sought to identify keyphrases embedded within them for tag cloud generation. In this paper, we propose a web content mining technique to extract keyphrases from web documents for tag cloud generation. Instead of using partial or full parsing, the proposed method applies n-gram technique followed by various heuristics-based refinements to identify a set of lexical and semantic features from text documents. We propose a rich set of domain-independent features to model candidate keyphrases very effectively for establishing their keyphraseness using classification models. We also propose a font-determination function to determine the relative font-size of keyphrases for tag cloud generation. The efficacy of the proposed method is established through experimentation. The proposed method outperforms the popular keyphrase extraction system KEA.

Q+Tree: An Efficient Quad Tree based Data Indexing for Parallelizing Dynamic and Reverse Skylines

Skyline queries play an important role in multi-criteria decision making applications of many areas. Given a dataset of objects, a skyline query retrieves data objects that are not dominated by any other data object in the dataset. Unlike standard skyline queries where the different aspects of data objects are compared directly, dynamic and reverse skyline queries adhere to the around-by semantics, which is realized by comparing the relative distances of the data objects w.r.t. a given query. Though, there are a number of works on parallelizing the standard skyline queries, only a few works are devoted to the parallel computation of dynamic and reverse skyline queries. This paper presents an efficient quad-tree based data indexing scheme, called Q+Tree, for parallelizing the computations of the dynamic and reverse skyline queries. We compare the performance of Q+Tree with an existing quad-tree based indexing scheme. We also present several optimization heuristics to improve the performance of both of the indexing schemes further. Experimentation with both real and synthetic datasets verifies the efficiency of the proposed indexing scheme and optimization heuristics.

Temporal tracking of congested partitions in dynamic urban road networks

With urban population rapidly growing, traffic congestion is becoming a major problem. In this paper, a framework is proposed for identifying the spatial congested partitions in a dynamic urban road network and for monitoring the temporal changes in their locations and structure. To that end, a given road network is transformed into a suitable graph representation, an initial partitioning based on a spectral clustering approach is performed, and then the partitions continue to be updated incrementally on the basis of the newly obtained traffic data at each new time point. The congested partitions are then identified on the basis of traffic measures (e.g., volume and green time utilization) available from the traffic signal control system. Experiments with the proposed method are conducted with real historical traffic data collected from the 493 signalized traffic sites in Melbourne, Victoria, Australia, with a total of 1,444 road segments and 581 intersection points. Experimental results show that large-scale urban traffic networks undergo many rapid but regular and frequent traffic patterns, which often go unnoticed by the traffic network operators. Tracking these kinds of changes in real time by means of the proposed framework can improve the reaction time of the traffic management team and result in less congestion.

Tracking the Evolution of Congestion in Dynamic Urban Road Networks

The congestion scenario on a road network is often represented by a set of differently congested partitions having homogeneous level of congestion inside. Due to the changing traffic, these partitions evolve with time. In this paper, we propose a two-layer method to incrementally update the differently congested partitions from those at the previous time point in an efficient manner, and thus track their evolution. The physical layer performs low-level computations to incrementally update a set of small-sized road network building blocks, and the logical layer provides an interface to query the physical layer about the congested partitions. At each time point, the unstable road segments are identified and moved to their most suitable building blocks. Our experimental results on different datasets show that the proposed method is much efficient than the existing re-partitioning methods without significant sacrifice in accuracy.