30099215
Indexing and incremental updating condensed data cube
OLAP (online analytical processing) servers usually pre-compute data cubes to improve the response time of possible aggregate queries over cuboids with different grouping attributes. To reduce the huge size of a sparse data cube, the base single tuples (BSTs) are explored to condense cube tuples aggregated from the same set of source tuples into one tuple, whenever such condensing will not require further aggregate when the cube is used to answer queries. We propose the CuboidTree to index the BST condensed cube. Using both synthetic and real world data, we conducted experiments to demonstrate query processing and bulk incremental updating performance of the indexing scheme.
45051194
2-PS Based Associative Text Classification
Recent studies reveal that associative classification can achieve higher accuracy than traditional approaches. The main drawback of this approach is that it generates a huge number of rules, which makes it difficult to select a subset of rules for accurate classification. In this study, we propose a novel association-based approach especially suitable for text classification. The approach first builds a classifier through a 2-PS (Two-Phase) method. The first phase aims for pruning rules locally, i.e., rules mined within every category are pruned by a sentence-level constraint, and this makes the rules more semantically correlated and less redundant. In the second phase, all the remaining rules are compared and selected with a global view, i.e., training examples from different categories are merged together to evaluate these rules. Moreover, when labeling a new document, the multiple sentence-level appearances of a rule are taken into account. Experimental results on the well-known text corpora show that our method can achieve higher accuracy than many well-known methods. In addition, the performance study shows that our method is quite efficient in comparison with other classification methods.
28964163
Hidden Conditioned Homomorphism for XPath Fragment Containment
As a query language for navigating XML trees and selecting a set of element nodes, XPath is ubiquitous in XML applications. One important issue of XPath queries is checking containment. In particular, we investigate a frequently used fragment of XPath that consists of node tests, the child axis (/), the descendant axis (//), branches ([]) and label wildcards (*). For special classes of pattern trees, the homomorphism algorithm returns false negatives. In order to address this problem, we propose two containment techniques, conditioned homomorphism and hidden conditioned homomorphism, and then present sound algorithms to check containment. The analytical result is given with an experiment.
15198141
Build Presentation Layer for Semantic Contents
Large scale of semantically enriched data is the foundation of the semantic web. We introduce the model used in SESQ system as the presentation layer of the semantic contents. It is an abstract graph independent of the data storage layer and application layer. Semantic contents of a specified domain are organized as nodes and arcs in the graph. GQML, a manipulation language, is designed for the graph, which is also used as the query language to semantic contents. With this model, the interoperation and integration of different sources will be easier. Now the model has been implemented on Berkley Database System and Relational Database.
16295185
2D/3D Web Visualization on Mobile Devices
Visualization is able to present the rich Web information intuitively and make the Web search/mining more productive. Mobile computing is able to provide the flexibility of working anytime and anywhere. Therefore, it is natural to combine the two techniques for intriguing applications. However, the technical limitations of mobile devices make it difficult to port well-designed visualization methods from desktop computers to mobile devices. In this paper, we present what we learned on engineering 3D Web visualization on both high-end and low-end mobile devices as the MWeb3D framework, which forms a distributed pipeline that move intensive computation from the mobile devices to server systems. Some important issues of this strategy include: (1) separating visualization from graphics rendering, (2) encoding visual presentation for transmitting via bandwidth-limited wireless connections, (3) user interaction on mobile devices, and (4) highly efficient graphics rendering on the mobile devices. We will show fruitful experiments on both PDA and mobile phone with photos taken from both simulator and real mobile devices.
9428764
OLAP Query Processing Algorithm Based on Relational Storage
When the relational storage method is adopted in the data warehouse system, the most time-consuming operations in OLAP query are multitable join and group-by aggregation. Based on the characteristics of the data warehouse itself and the applications run on it, one new multi-table join algorithm -- Mjoin is given in this paper. And the performance of this new Mjoin algorithm is improved greatly, compared with other traditional multitable join algorithms. In this paper, a new sorting based group-by aggregation algorithm -- MuSA is also given, based on the Mjoin algorithm. The speed of sorting is remarkably improved in this new sorting based aggregation algorithm, as the keyword mapping technology is used to compress the sort keywords in the course of sorting.
8920901
Exploit Sequencing to Accelerate XML Twig Query Answering
Speeding up query evaluation in large XML repositories becomes a challenging and all-important problem with vast XML-related applications arising. In this paper, we present SCALER, an efficient algorithm for XML query answering based on UDFTS and effective twig structure matching scheme. UDFTS not only constructs a one-to-one correspondence between trees and sequences but also maintains critical parent-child relationships for twig structure matching. With SCALER, XML queries can be performed by subsequence matching without breaking twigs into sub paths and evaluating these paths individually. Thus, costly join operations can be avoided elegantly. We also show the correctness of query answering by eliminating false dismissals and false alarms naturally in SCALER. By a thorough experimental study on various real-life data, we prove the efficiency and scalability of SCALER over the previous known alternative.