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Gaussian mixture model (GMM) has been widely used in fields of image processing and investment data mining. However, in many practical applications, the number of the components is not known. This paper proposes a kind of greedy merge EM (GMEM) learning algorithm such that the number of Gaussians can be determined automatically with the minimum message length (MML) criterion. Moreover, the greedy...
With the development of Web 2.0 technologies, Web-based social network (WBSN) becomes a fast developing field in recent years. As there are a large number of participants on the open platforms of WBSNs, trust relation is a critical issue. In this paper, we study the features of WBSN web sites and some trust relevant models for WBSNs. We further propose a new category of "three generations of...
Support vector machine is effective method for resolving non-liner classification and regression problem, but it is sensitive to the noises and outliers in the training samples. In order to overcome this problem, fuzzy support vector machine (FSVM) is introduced. How to choose a proper fuzzy membership is very important for the practical problem in FSVM. Generally, fuzzy membership is built according...
Three-level AC switch unit is produced by two-level AC switch unit connected together in series manner. Basic three-level converter is produced by applying three-level AC switch unit in basic converter. Combination mode three-level converter is obtained by combining two basic three-level converters, and it is improved into combination mode three-level converter with input and output sharing the same...
Zeta mode three-level AC/AC converter can realize three-level voltage before output filter, which can get a better spectrum and reduce bulk of the filter. Compared with non-isolation and low or middle frequency isolation AC/DC/AC converters, it is single stage. And compared with Buck non-isolation AC/AC converter which can only realize buck output voltage, it can realize buck and boost output voltage...
At present, the primary methods of realizing AC/AC voltage transformation are frequency transformer, AC-DC-AC converter, matrix converter, high-frequency link AC/AC converters and single-stage AC/AC converters. In areas of high power conversion, taking into account to converter's cost and the quality of output voltage, bridge mode AC/AC converter has some advantages. This converter can realize electrical...
A dual-polarized phased array antenna for synthetic aperture radar (SAR) application is introduced in this paper. The RF topology configuration is illuminated briefly. An antenna module was tested and the measured results are presented, with which an applied array antenna should be extended with RF distribution networks, power supply and control subsystem used.
With the rapid development of text summarization, evaluation methods for automatic summarization system is becoming more and more important in natural language processing, which can promote development of text summarization greatly. This paper analyzes the existed methods for automatic summarization evaluation, and introduces a new evaluation method based on HowNet. The original tests have shown that...
Because of many duplicated web pages existing on the web, search engines need to find and remove them, not only for saving process time and hardware resource, but also for ensuring that users can get the result information without many replicas. In this paper, we propose a method to find and remove duplicated Chinese Web pages for search engine. First we describe a scheme based on semantic keywords...
Trust is a critical issue in e-commerce and e-service environments. Some applications (such as eBay) have introduced various trust management mechanisms to provide valuable information to buyers prior to placing orders and making payments. While trust has been actively studied in the research community, some malicious sellers and fraudulent transactions still widely exist. A typical attack is to entice...
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