Soheila Ashkezari | Ferdowsi University of Mashhad (original) (raw)

Papers by Soheila Ashkezari

Electric Power Components and Systems, 2012

Timely and accurate assessment of voltage and power flow security is necessary to detect post-con... more Timely and accurate assessment of voltage and power flow security is necessary to detect post-contingency problems in order to prevent a large-scale blackout. This article presents an enhanced radial basis function neural network based on a modified training algorithm for on-line ranking of the contingencies expected to cause steady-state bus voltage and power flow violations. Hidden layer neurons have been

Ng. Jordan Weiss (NJW) is one of the most widely used spectral clustering algorithms. For partiti... more Ng. Jordan Weiss (NJW) is one of the most widely used spectral clustering algorithms. For partitioning data into clusters, this method uses the largest eigenvectors of the normalized affinity matrix derived from the data set. However, this set of features is not always the best selection to represent and reveal the structure of the data. In this paper, we aim to propose a quadratic framework to select the most representative eigenvectors. In this way, we define an objective function which includes two factors. In the first part, the interaction of each pair of eigenvectors is considered. In the second part, the ability of each eigenvector to represent the structure of data is considered separately. Then, we use proposed Tabu Search in [1] to solve this mixed-integer quadratic optimization problem. The experimental results show the success of this method to select relevant eigenvectors.

International Journal of Signal …, Jan 1, 2011

Spectral clustering is a powerful technique in clustering specially when the structure of data is... more Spectral clustering is a powerful technique in clustering specially when the structure of data is not linear and classical clustering methods lead to fail. In this paper, we propose a spectral clustering algorithm with a feature selection schema based on extracted features of Kernel PCA. In the proposed algorithm, selecting appropriate vectors is dependent upon entropy of clusters on these vectors and weighting method is influenced by sum of the existence gap between clusters and entropy of the vectors. Tuning the parameters has a great effect on the results of spectral clustering techniques. In the ideal case, comparing our method with NJW and Kernel K-Means indicate the successful of the proposed algorithm.

Many vision tasks are based on edge/corner detection. We propose some rules and utilize them to f... more Many vision tasks are based on edge/corner detection. We propose some rules and utilize them to find suitable window for edge/corner detection by using quadratic programming. Experimental results over synthetic images and real images show satisfactory outcomes.

2010 World Congress …, Jan 1, 2010

The World Wide Web has created a new media for mass marketing that can also be highly customized ... more The World Wide Web has created a new media for mass marketing that can also be highly customized to online customers’ needs and expectations. Recommender Systems (RS) play an important role in this area. Here, we aim to establish a genre-based collaborative RS to automatically suggest and rank a list of appropriate items (movies) to a user based on the user profile and the past voting patterns of other users with similar tastes. The contribution of this paper is using genre based information in a hybrid fuzzy-Bayesian network collaborative RS. The interest to the different genres is computed based on a hybrid user model. The similarity of likeminded users according to the fuzzy distance and also Pearson correlation coefficient is involved in a Bayesian network.

Electric Power Components and Systems, 2012

Timely and accurate assessment of voltage and power flow security is necessary to detect post-con... more Timely and accurate assessment of voltage and power flow security is necessary to detect post-contingency problems in order to prevent a large-scale blackout. This article presents an enhanced radial basis function neural network based on a modified training algorithm for on-line ranking of the contingencies expected to cause steady-state bus voltage and power flow violations. Hidden layer neurons have been

Ng. Jordan Weiss (NJW) is one of the most widely used spectral clustering algorithms. For partiti... more Ng. Jordan Weiss (NJW) is one of the most widely used spectral clustering algorithms. For partitioning data into clusters, this method uses the largest eigenvectors of the normalized affinity matrix derived from the data set. However, this set of features is not always the best selection to represent and reveal the structure of the data. In this paper, we aim to propose a quadratic framework to select the most representative eigenvectors. In this way, we define an objective function which includes two factors. In the first part, the interaction of each pair of eigenvectors is considered. In the second part, the ability of each eigenvector to represent the structure of data is considered separately. Then, we use proposed Tabu Search in [1] to solve this mixed-integer quadratic optimization problem. The experimental results show the success of this method to select relevant eigenvectors.

International Journal of Signal …, Jan 1, 2011

Spectral clustering is a powerful technique in clustering specially when the structure of data is... more Spectral clustering is a powerful technique in clustering specially when the structure of data is not linear and classical clustering methods lead to fail. In this paper, we propose a spectral clustering algorithm with a feature selection schema based on extracted features of Kernel PCA. In the proposed algorithm, selecting appropriate vectors is dependent upon entropy of clusters on these vectors and weighting method is influenced by sum of the existence gap between clusters and entropy of the vectors. Tuning the parameters has a great effect on the results of spectral clustering techniques. In the ideal case, comparing our method with NJW and Kernel K-Means indicate the successful of the proposed algorithm.

Many vision tasks are based on edge/corner detection. We propose some rules and utilize them to f... more Many vision tasks are based on edge/corner detection. We propose some rules and utilize them to find suitable window for edge/corner detection by using quadratic programming. Experimental results over synthetic images and real images show satisfactory outcomes.

2010 World Congress …, Jan 1, 2010

The World Wide Web has created a new media for mass marketing that can also be highly customized ... more The World Wide Web has created a new media for mass marketing that can also be highly customized to online customers’ needs and expectations. Recommender Systems (RS) play an important role in this area. Here, we aim to establish a genre-based collaborative RS to automatically suggest and rank a list of appropriate items (movies) to a user based on the user profile and the past voting patterns of other users with similar tastes. The contribution of this paper is using genre based information in a hybrid fuzzy-Bayesian network collaborative RS. The interest to the different genres is computed based on a hybrid user model. The similarity of likeminded users according to the fuzzy distance and also Pearson correlation coefficient is involved in a Bayesian network.