Time filter

Source Type

Han D.,Northeastern University China | Han D.,Key Laboratory of Medical Image Computing NEU | Giraud-Carrier C.,Brigham Young University | Li S.,Northeastern University China
Applied Intelligence | Year: 2015

Currently available algorithms for data streams classification are mostly designed to deal with precise and complete data. However, data in many real-life applications is naturally uncertain due to inherent instrument inaccuracy, wireless transmission error, and so on. We propose UELM-MapReduce, a parallel ensemble classifier based on Extreme Learning Machine (ELM) and MapReduce for handling uncertain data streams. We train an efficient parallel ELM-based ensemble classifier from sequential training chunks of the uncertain data streams. The weight of each base classifier in the ensemble is adjusted according to its mean square error on the up-to-date test chunk, and the classifier with the lowest accuracy is replaced. UELM-MapReduce can classify uncertain data streams with both efficiency and accuracy while effectively handling concept drift. Experimental results demonstrate that UELM-MapReduce has better performance than other methods in prediction accuracy and computational efficiency. © 2015 Springer Science+Business Media New York Source

Cao K.,Northeastern University China | Shi L.,PLA Logistical Engineering University | Wang G.,Northeastern University China | Wang G.,Key Laboratory of Medical Image Computing NEU | And 2 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2014

Outlier detection is one of the key problems in the data mining area which can reveal rare phenomena and behaviors. In this paper, we will examine the problem of density-based local outlier detection on uncertain data sets described by some discrete instances. We propose a new density-based local outlier concept based on uncertain data. In order to quickly detect outliers, an algorithm is proposed that does not require the unfolding of all possible worlds. The performance of our method is verified through a number of simulation experiments. The experimental results show that our method is an effective way to solve the problem of density-based local outlier detection on uncertain data. © 2014 Springer International Publishing Switzerland. Source

Han D.-H.,Northeastern University China | Zhang X.,Northeastern University China | Wang G.-R.,Northeastern University China | Wang G.-R.,Key Laboratory of Medical Image Computing NEU
Journal of Computer Science and Technology | Year: 2015

Conventional classification algorithms are not well suited for the inherent uncertainty, potential concept drift, volume, and velocity of streaming data. Specialized algorithms are needed to obtain efficient and accurate classifiers for uncertain data streams. In this paper, we first introduce Distributed Extreme Learning Machine (DELM), an optimization of ELM for large matrix operations over large datasets. We then present Weighted Ensemble Classifier Based on Distributed ELM (WE-DELM), an online and one-pass algorithm for efficiently classifying uncertain streaming data with concept drift. A probability world model is built to transform uncertain streaming data into certain streaming data. Base classifiers are learned using DELM. The weights of the base classifiers are updated dynamically according to classification results. WE-DELM improves both the efficiency in learning the model and the accuracy in performing classification. Experimental results show that WE-DELM achieves better performance on different evaluation criteria, including efficiency, accuracy, and speedup. © 2015, Springer Science+Business Media New York. Source

Ding G.,Key Laboratory of Medical Image Computing NEU | Ding G.,Northeastern University China | Wang G.,Key Laboratory of Medical Image Computing NEU | Wang G.,Northeastern University China
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

Attribute-level schema matching is a critical step in numerous database applications, such as DataSpaces, Ontology Merging and Schema Integration. There exist many researches on this topic, however, they ignore the implicit categorical information which is crucial to find high-quality matches between schema attributes. In this paper, we discover the categorical semantics implicit in source instances, and associate them with the matches in order to improve overall quality of schema matching. Our method works in three phases. The first phase is a pre-detecting step that detects the possible categories of source instances by using clustering techniques. In the second phase, we employ information entropy to find the attributes whose instances imply the categorical semantics. In the third phase, we introduce a new concept c-mapping to represent the associations between the matches and the categorical semantics. Then, we employ an adaptive scoring function to evaluate the c-mappings to achieve the task of associating the matches with the semantics. Moreover, we show how to translate the matches with semantics into schema mapping expressions, and use the chase procedure to transform source data into target schemas. An experimental study shows that our approach is effective and has good performance. © 2011 Springer-Verlag. Source

Sun Y.,Key Laboratory of Medical Image Computing NEU | Sun Y.,Northeastern University China | Yuan Y.,Key Laboratory of Medical Image Computing NEU | Yuan Y.,Northeastern University China | And 2 more authors.
Neurocomputing | Year: 2011

Although classification in centralized environments has been widely studied in recent years, it is still an important research problem for classification in P2P networks due to the popularity of P2P computing environments. The main target of classification in P2P networks is how to efficiently decrease prediction error with small network overhead. In this paper, we propose an OS-ELM based ensemble classification framework for distributed classification in a hierarchical P2P network. In the framework, we apply the incremental learning principle of OS-ELM to the hierarchical P2P network to generate an ensemble classifier. There are two kinds of implementation methods of the ensemble classifier in the P2P network, one-by-one ensemble classification and parallel ensemble classification. Furthermore, we propose a data space coverage based peer selection approach to reduce high the communication cost and large delay. We also design a two-layer index structure to efficiently support peer selection. A peer creates a local Quad-tree to index its local data and a super-peer creates a global Quad-tree to summarize its local indexes. Extensive experimental studies verify the efficiency and effectiveness of the proposed algorithms. © 2011 Elsevier B.V. Source

Discover hidden collaborations