Nowadays, content-based image retrieval (CBIR) is the mainstay of image retrieval systems. To be more profitable, relevance feedback techniques were incorporated into CBIR such that more precise results can be obtained by taking user’s feedbacks into account. However, existing relevance feedback-based CBIR methods usually request a number of iterative feedbacks to produce refined search results, […]
Archives for June 2011
Cosdes: A Collaborative Spam Detection System with a Novel
E-mail communication is indispensable nowadays, but the e-mail spam problem continues growing drastically. In recent years, the notion of collaborative spam filtering with near-duplicate similarity matching scheme has been widely discussed. The primary idea of the similarity matching scheme for spam detection is to maintain a known spam database, formed by user feedback, to block […]
Anonymous Publication of Sensitive Transactional Data
Existing research on privacy-preserving data publishing focuses on relational data: in this context, the objective is to enforce privacy-preserving paradigms, such as k-anonymity and ‘-diversity, while minimizing the information loss incurred in the anonymizing process (i.e., maximize data utility). Existing techniques work well for fixed-schema data, with low dimensionality. Nevertheless, certain applications require privacy-preserving publishing […]
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 […]
A BIDIRECTIONAL UPS INVERTER UTILISING HIGH FREQUENCY CENTER-TAPPED TRANSFORMER-Matlab-Power Electronics-2008
A new variation of transformer-isolated inverter for UPS application is proposed. It is basically similar to the circuit proposed by Koutroulis with the following modifications: 1) a modified modulation technique for the HF PWM inverter stage and 2) replacing the full bridge active rectifier with a center-tapped active rectifier. With these modifications, the switches count […]
Fundamental Frequency Switching Strategies of a Seven-Level Hybrid Cascaded H-Bridge Multilevel Inverter-Matlab-Power Electronics-2009
This paper presents a cascaded H-bridge multilevel inverter that can be implemented using only a single dc power source and capacitors. Standard cascaded multilevel inverters require n dc sources for 2n + 1 levels. Without requiring transformers,the scheme proposed here allows the use of a single dc power source (e.g., a battery or a fuel […]
A Hybrid Wind-Solar Energy System: A New Rectifier Stage Topology-Matlab-Power Electronics-2010
Environmentally friendly solutions are becoming more prominent than ever as a result of concern regarding the state of our deteriorating planet. This paper presents a new system configuration of the front-end rectifier stage for a hybrid wind/photovoltaic energy system. This configuration allows the two sources to supply the load separately or imultaneously depending on the […]
Multistring Five-Level Inverter With Novel PWM Control Scheme for PV Application-Matlab-Power Electronics-2010
This paper presents a single-phase multistring five-level photovoltaic (PV) inverter topology for grid-connected PV systems with a novel pulsewidth-modulated (PWM) control scheme. Three PV strings are cascaded together in parallel configuration and connected to a five-level inverter to produce output voltage in five levels: zero, +1/2Vdc, Vdc, −1/2Vdc, and −Vdc. Two reference signals that were […]
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 […]
Capacitor Balance Issues of the Diode-Clamped Multilevel Inverter Operated in a Quasi Two-State Mode-Matlab-Power Electronics-2008
A new operational mode for diode-clamped multilevel inverters termed quasi two-level operation is proposed. Such operation aims to avoid the imbalance problem of the dc-link capacitors for multilevel inverters with more than three levels and reduces the dc-link capacitance without introducing any significant voltage ripple at the dc-link nodes. The proposed operation can be generalized […]
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