Reza Ebrahimpour

Prof. Reza Ebrahimpour


Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
12 May 2012 in Artificial Intelligence Review
Verified
Journal Article
Closed access
PDF file
SMSaeed Masoudnia
Saeed Masoudnia
REReza Ebrahimpour
Reza Ebrahimpour

15 May 2019 in PLOS Computational Biology
Verified
Journal Article
Open access
PDF file
KRKarim Rajaei
Karim Rajaei
YMYalda Mohsenzadeh
Yalda Mohsenzadeh
REReza Ebrahimpour
Reza Ebrahimpour
SKSeyed-Mahdi Khaligh-Razavi
Seyed-Mahdi Khaligh-Razavi
Core object recognition, the ability to rapidly recognize objects despite variations in their appearance, is largely solved through the feedforward processing of visual information. Deep neural networks are shown to achieve human-level performance in these tasks, and explain the primate brain representation. On the other hand, object recognition under more challenging conditions (i.e. beyond the core recognition problem) is less characterized. One such example is object recognition under occlusion. It is unclear to what extent feedforward and recurrent processes contribute in object recognition under occlusion. Furthermore, we do not know whether the conventional deep neural networks, such as AlexNet, which were shown to be successful in solving core object recognition, can perform similarly well in problems that go beyond the core recognition. Here, we characterize neural dynamics of object recognition under occlusion, using magnetoencephalography (MEG), while participants were presented with images of objects with various levels of occlusion. We provide evidence from multivariate analysis of MEG data, behavioral data, and computational modelling, demonstrating an essential role for recurrent processes in object recognition under occlusion. Furthermore, the computational model with local recurrent connections, used here, suggests a mechanistic explanation of how the human brain might be solving this problem. In recent years, deep-learning-based computer vision algorithms have been able to achieve human-level performance in several object recognition tasks. This has also contributed in our understanding of how our brain may be solving these recognition tasks. However, object recognition under more challenging conditions, such as occlusion, is less characterized. Temporal dynamics of object recognition under occlusion is largely unknown in the human brain. Furthermore, we do not know if the previously successful deep-learning algorithms can similarly achieve human-level performance in these more challenging object recognition tasks. By linking brain data with behavior, and computational modeling, we characterized temporal dynamics of object recognition under occlusion, and proposed a computational mechanism that explains both behavioral and the neural data in humans. This provides a plausible mechanistic explanation for how our brain might be solving object recognition under more challenging conditions.

22 July 2012 in Neural Computing and Applications
Verified
Journal Article
Closed access
PDF file
AAAmir Ahangi
Amir Ahangi
MKMehdi Karamnejad
Mehdi Karamnejad
NMNima Mohammadi
Nima Mohammadi
REReza Ebrahimpour
Reza Ebrahimpour
Nasour BagheriNasour Bagheri
Nasour Bagheri

4 September 2013 in EURASIP Journal on Advances in Signal Processing
Verified
Journal Article
Open access
PDF file
Nasour BagheriNasour Bagheri
Nasour Bagheri
REReza Ebrahimpour
Reza Ebrahimpour
NGNavid Ghaedi
Navid Ghaedi
In this paper, we present two differential fault analyses on PRESENT-80 which is a lightweight block cipher. The first attack is a basic attack which induces a fault on only one bit of intermediate states, and we can obtain the last subkey of the block cipher, given 48 faulty cipher texts on average. The second attack can retrieve the master key of the block cipher, given 18 faulty cipher texts on average. In the latter attack, we assume that we can induce faults on a single nibble of intermediate states. Given those faulty cipher texts, the computational complexity of attacks is negligible.

26 October 2011 in PLOS ONE
Verified
Journal Article
Open access
PDF file
MJMehrdad Javadi
Mehrdad Javadi
REReza Ebrahimpour
Reza Ebrahimpour
ASAtena Sajedin
Atena Sajedin
SFSoheil Faridi
Soheil Faridi
SZShokoufeh Zakernejad
Shokoufeh Zakernejad
This paper illustrates the use of a combined neural network model based on Stacked Generalization method for classification of electrocardiogram (ECG) beats. In conventional Stacked Generalization method, the combiner learns to map the base classifiers' outputs to the target data. We claim adding the input pattern to the base classifiers' outputs helps the combiner to obtain knowledge about the input space and as the result, performs better on the same task. Experimental results support our claim that the additional knowledge according to the input space, improves the performance of the proposed method which is called Modified Stacked Generalization. In particular, for classification of 14966 ECG beats that were not previously seen during training phase, the Modified Stacked Generalization method reduced the error rate for 12.41% in comparison with the best of ten popular classifier fusion methods including Max, Min, Average, Product, Majority Voting, Borda Count, Decision Templates, Weighted Averaging based on Particle Swarm Optimization and Stacked Generalization.

1 May 2019 in Neuroscience
Verified
Journal Article
Closed access
SSShirin Vafaei Shooshtari
Shirin Vafaei Shooshtari
JSJamal Esmaily Sadrabadi
Jamal Esmaily Sadrabadi
ZAZahra Azizi
Zahra Azizi
REReza Ebrahimpour
Reza Ebrahimpour