33260694
Consistent Answers from Integrated XML Data
We consider the problem of using query transformation to compute consistent answers when queries are posed to virtual XML data integration systems, which are specified following the local-as-view approach. This is achieved in two steps. First the given query is transformed to a new query with global constraints considered, then the new query is rewritten to queries on the underlying data sources by reversing rules in view definitions. The XPath query on the global system can be transformed in XQuery. We implement prototypes of our method, and evaluate our framework and algorithms in the experiment.
207162632
Utility-based anonymization for privacy preservation with less information loss
Privacy becomes a more and more serious concern in applications involving microdata. Recently, efficient anonymization has attracted much research work. Most of the previous methods use global recoding, which maps the domains of the quasi-identifier attributes to generalized or changed values. However, global recoding may not always achieve effective anonymization in terms of discernability and query answering accuracy using the anonymized data. Moreover, anonymized data is often used for analysis. As well accepted in many analytical applications, different attributes in a data set may have different utility in the analysis. The utility of attributes has not been considered in the previous methods.
 In this paper, we study the problem of utility-based anonymization. First, we propose a simple framework to specify utility of attributes. The framework covers both numeric and categorical data. Second, we develop two simple yet efficient heuristic local recoding methods for utility-based anonymization. Our extensive performance study using both real data sets and synthetic data sets shows that our methods outperform the state-of-the-art multidimensional global recoding methods in both discernability and query answering accuracy. Furthermore, our utility-based method can boost the quality of analysis using the anonymized data.
30881426
Constraint-Based Graph Mining in Large Database
Currently, constraints are increasingly considered as a kind of means of user- or expert-control for filtering those unsatisfied and redundant patterns rapidly during the web mining process. Recent work has highlighted the importance of constraint-based mining paradigm in the context of frequent itemsets, sequences, and many other interesting patterns in large database. However, it is still not clear how to push various constraints systematically into graph mining process. In this paper, we categorize various graph-based constraints into several major classes and develop a framework CabGin (i.e. C onstr a int- b ased G raph M in ing) to push them into mining process by their categories. Non-monotonic aggregates like average also can be pushed into CabGin with minor revision. Experimental results show that CabGin can prunes a large search space effectively by pushing graph-based constraints into mining process.
34121335
Data-Aware Clustering Hierarchy for Wireless Sensor Networks
In recent years, the wireless sensor network (WSN) is employed a wide range of applications. But existing communication protocols for WSN ignore the characteristics of collected data and set routes only according to the mutual distance and residual energy of sensors. In this paper we propose a Data-Aware Clustering Hierarchy (DACH), which organizes the sensors based on both distance information and data distribution in the network Furthermore, we also present a multi-granularity query processing method based on DACH, which can estimate the query result more efficiently. Our empirical study shows that DACH has higher energy efficiency than Low-Energy Adaptive Clustering Hierarchy (LEACH), and the multi-granularity query processing method based on DACH brings more accurate results than a random access system using same cost of energy.
10409272
Repairing Inconsistent XML Documents
XML document may contain inconsistencies that violate predefined integrity constraints, and there are two basic concepts for this problem: Repair is the data consistent with the integrity constraints, and also minimally differs from the original one. Consistent data is the data common for every possible repair. In this paper, first we give a general constraint model for XML, which can express functional dependencies, keys and multivalued dependencies. Next we provide a repair framework for inconsistent XML document with three basic update operations: node insertion, node deletion and value modification. Following this approach, we introduce the concept of repair for inconsistent XML document, discuss the chase process to generate repairs, and prove some important properties of the chase process. Finally we give a method to obtain the greatest lower bound of all possible repairs, which is sufficient for consistent data.
8249361
SUDEPHIC: Self-Tuning Density-Based Partitioning and Hierarchical Clustering
Clustering is one of the primary techniques in data mining, for which to find the user expecting result is a major issue. However, to dynamically specify the parameters for clustering algorithms presents an obstacle for users. This paper firstly introduces a novel density-based partitioning and hierarchical algorithm, which makes it easy to employ synthetic feedback mechanism in clustering. Additionally, by investigating into the relation between parameters and the clustering result, we propose a self-tuning technique for the setting of parameters. Meanwhile, the density distribution within a cluster can be expressed in the result for the user to specify the cluster’s feature. The algorithm is both evaluated in theory and practice. It outperforms many existing algorithms both in efficiency and quality.
12021051
COE: A General Approach for Efficient Genome-Wide Two-Locus Epistasis Test in Disease Association Study
The availability of high density single nucleotide polymorphisms (SNPs) data has made genome-wide association study computationally challenging. Two-locus epistasis (gene-gene interaction) detection has attracted great research interest as a promising method for genetic analysis of complex diseases. In this paper, we propose a general approach, COE, for efficient large scale gene-gene interaction analysis, which supports a wide range of tests. In particular, we show that many commonly used statistics are convex functions. From the observed values of the events in two-locus association test, we can develop an upper bound of the test value. Such an upper bound only depends on single-locus test and the genotype of the SNP-pair. We thus group and index SNP-pairs by their genotypes. This indexing structure can benefit the computation of all convex statistics. Utilizing the upper bound and the indexing structure, we can prune most of the SNP-pairs without compromising the optimality of the result. Our approach is especially efficient for large permutation test. Extensive experiments demonstrate that our approach provides orders of magnitude performance improvement over the brute force approach.
15503361
AB-Index: An Efficient Adaptive Index for Branching XML Queries
Query-adaptive XML indexing has been proposed and shown to be an efficient way to accelerate XML query processing, because it dynamically adapts to the workload. However, existing adaptive index lack of support for branching queries, and also with low efficiency for query processing and adaptation operations. In this paper, we propose a new Adaptive index for Branching queries, which is named as AB-Index. It is designed to support XML path queries with branching predicates. Efficient index construction, query processing, and index adaptation algorithms are proposed for AB-Index. In the experiments, the proposed index is demonstrated to outperform the state-of-the-art approach in the area of adaptive index in terms of query and adaptation efficiencies.
3430950
Efficient Processing of XML Path Queries Using the Disk-based F&B Index
With the proliferation of XML data and applications on the Internet, efficient XML query processing techniques are in great demand. Answering queries using XML indexes is a natural approach. A number of XML indexes have been proposed in the literature: among them, FB the result is a disk-based F&B Index with good clustering properties. In addition, novel query processing algorithms exploiting the physical organization of the disk-based F&B Indexes are proposed. Experimental results verify that our disk-based F&B Index can scale up for large data size with good query performance compared with state-of-the-art XML query processing algorithms.
19006089
Processing of massive audit data streams for real-time anomaly intrusion detection
Intrusion detection is an important technique in the defense-in-depth network security framework. Most current intrusion detection models lack the ability to process massive audit data streams for real-time anomaly detection. In this paper, we present an effective anomaly intrusion detection model based on Principal Component Analysis (PCA). The model is more suitable for high speed processing of massive data streams in real-time from various data sources by considering the frequency property of audit events than by use of the transition property or the correlation property. It can serve as a general framework that a practical Intrusion Detection Systems (IDS) can be implemented in various computing environments. In this method, a multi-pronged anomaly detection model is used to monitor various computer system and network behaviors. Three sources of data, system call data from the University of New Mexico (lpr) and from KLINNS Lab of Xi'an Jiaotong University (ftp), shell command data from AT&T Research laboratory, and network data from MIT Lincoln Lab, are used to validate the model and the method. The frequencies of individual system calls generated by one process and of individual commands embedded in one command block as well as features extracted in one network connection are transformed into an input data vector. Our method is employed to reduce the high dimensional data vectors and thus the detection is handled in a lower dimension with high efficiency and low use of system resources. The distance between a vector and its reconstruction in the reduced subspace is used for anomaly detection. Empirical results show that our model is promising in terms of detection accuracy and computational efficiency, and thus amenable for real-time intrusion detection.
90043
A new approach to design robust backstepping controller for MIMO nonlinear systems with input unmodeled dynamics
In this paper, a new scheme inspired by the idea of decentralized control methodology is proposed to design output feedback controllers for a class of MIMO nonlinear systems with input unmodeled dynamics. With dynamic normalization and backstepping approach, the destabilizing effects of unmodeled dynamics depending on inputs are compensated and global uniform boundedness of all the signals in the closed loop system is established for sufficiently weak input unmodeled dynamics.