Online learning algorithms often have to operate in the presence of concept drifts. A recent study revealed that different diversity levels in an ensemble of learning machines are required in order to maintain high generalization on both old and new concepts. Inspired by this study and based on a further study of diversity with different […]
Throughput Optimization in High Speed Downlink Packet Access (HSDPA)
In this paper, we investigate single user throughput optimization in High Speed Downlink Packet Access (HSDPA). Specifically, we propose offline and online optimization algorithms which adjust the Channel Quality Indicator (CQI) used by the network for scheduling of data transmission. In the offline algorithm, a given target block error rate (BLER) is achieved by adjusting […]
A Query Formulation Language for the Data Web
We present a query formulation language (called MashQL) in order to easily query and fuse structured data on the web. The main novelty of MashQL is that it allows people with limited IT-skills to explore and query one (or multiple) data sources without prior knowledge about the schema, structure, vocabulary, or any technical details of […]
Query Planning for Continuous Aggregation Queries over a Network of Data Aggregators
Continuous queries are used to monitor changes to time varying data and to provide results useful for online decision making. Typically a user desires to obtain the value of some aggregation function over distributed data items, for example, to know value of portfolio for a client; or the AVG of temperatures sensed by a set […]
Scalable Learning of Collective Behavior
This study of collective behavior is to understand how individuals behave in a social networking environment. Oceans of data generated by social media like Facebook, Twitter, Flickr, and YouTube present opportunities and challenges to study collective behavior on a large scale. In this work, we aim to learn to predict collective behavior in social media. […]
Document Clustering in Correlations Similarity Measure Space
This paper presents a new spectral clustering method called correlation preserving indexing (CPI), which is performed in the correlation similarity measure space. In this framework, the documents are projected into a low-dimensional semantic space in which the correlations between the documents in the local patches are maximized while the correlations between the documents outside these […]
A Fuzzy Self-Constructing Feature Clustering Algorithm for Text Classification
Feature clustering is a powerful method to reduce the dimensionality of feature vectors for text classification. In this paper, we propose a fuzzy similarity-based self-constructing algorithm for feature clustering. The words in the feature vector of a document set are grouped into clusters, based on similarity test. Words that are similar to each other are […]
Improved Z-Source Inverter With Reduced Z-Source Capacitor Voltage Stress and Soft-Start Capability-Matlab-Power Electronics-2009
This paper proposes an improved Z-source inverter topology. Compared to the traditional Z-source inverter, it can reduce the Z-source capacitor voltage stress ignificantly to perform the same voltage boost, and has inherent limitation to inrush current at startup. The control strategy of the proposed Z-source inverter is exactly the same as the traditional one, so […]
Photovoltaic Parallel Resonant DC-link Soft Switching Inverter using Hysteresis Current Control-Matlab-Power Electronics-2010
This paper proposes a photovoltaic parallel resonant dc-link soft switching inverter using hysteresis current control.The proposed system includes a dc-link switch for soft switching. When the dc-link switch is turned off, the inverter switches are turned on and off with zero voltage switching using hysteresis current controller. So, all of the switches in the proposed […]
Quasi-Z-Source Inverter for Photovoltaic Power Generation Systems-Matlab-Power Electronics-2009
This paper presents a quasi-Z-source inverter (qZSI) that is a new topology derived from the traditional Z-source inverter (ZSI). The qZSI inherits all the advantages of the ZSI,which can realize buck/boost, inversion and power conditioning in a single stage with improved reliability. In addition, the proposed qZSI has the unique advantages of lower component ratings […]