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S. Ehsan

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Rafael Abargues

Universitat de València

Ulyanovsk State University

Viacheslav Kuleshov

Stockholm University

Stephen W Merkel

Vrije Universiteit Amsterdam

VIT University

Ana L. Albarran Lara

University of California, Los Angeles

Dirk Lachenmeier

Carlos Luna Criado

Universidad Autónoma de Nuevo León

Universidade Federal do Rio Grande do Norte

Samsun Ondokuz Mayis University

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Papers by S. Ehsan

Data Loss Modeling and Analysis in Partially-Covered Delay-Tolerant Networks

2011 Proceedings of 20th International Conference on Computer Communications and Networks (ICCCN), 2011

... Kyle Bradford, Max Brugger, Samina Ehsan, Bechir Hamdaoui, Yevgeniy Kovchegov ... The main co... more

Evaluating the angular sensitivity of corner detectors

2011 IEEE International Conference on Virtual Environments, Human-Computer Interfaces and Measurement Systems Proceedings, 2011

Several popular corner detectors were evaluated on imagery containing corners with a variety of i... more Several popular corner detectors were evaluated on imagery containing corners with a variety of internal angles. Even in a noise-free environment, differences in performance were found. A null hypothesis approach was taken in evaluating whether these performance differences were significant, taking into account correctly the size of the dataset and the number of discrepancies. It was found that some of these performance differences are statistically significant, allowing recommendations to be made regarding which detectors should be used when a problem has corners of known internal angles.

Dynamically sampled multivariate empirical mode decomposition

Electronics Letters, 2015

Measuring the Coverage of Interest Point Detectors

Lecture Notes in Computer Science, 2011

Repeatability is widely used as an indicator of the performance of an image feature detector but,... more Repeatability is widely used as an indicator of the performance of an image feature detector but, although useful, it does not convey all the information that is required to describe performance. This paper explores the spatial distribution of interest points as an alternative indicator of performance, presenting a metric that is shown to concur with visual assessments. This metric is then extended to provide a measure of complementarity for pairs of detectors. Several state-of-the-art detectors are assessed, both individually and in combination. It is found that Scale Invariant Feature Operator (SFOP) is dominant, both when used alone and in combination with other detectors.

A statistical approach for comparing the performances of corner detectors

Proceedings of 2011 IEEE Pacific Rim Conference on Communications, Computers and Signal Processing, 2011

Corner detectors are widely used in computer vision. This paper assesses several state-of-the-art... more Corner detectors are widely used in computer vision. This paper assesses several state-of-the-art corner detectors in terms of overall performance and the internal angles of corners using simple geometric shapes. This assessment is carried out using a statistically-valid null hypothesis approach, not previously used in computer vision. It is found that there are statistically significant differences in performance. Moreover, the null hypothesis approach is easy to use in comparing vision techniques.

Memory-Efficient Design Strategy for a Parallel Embedded Integral Image Computation Engine

2011 Irish Machine Vision and Image Processing Conference, 2011

ABSTRACT In embedded vision systems, parallel computation of the integral image presents several ... more ABSTRACT In embedded vision systems, parallel computation of the integral image presents several design challenges in terms of hardware resources, speed and power consumption. Although recursive equations significantly reduce the number of operations for computing the integral image, the required internal memory becomes prohibitively large for an embedded integral image computation engine for increasing image sizes. With the objective of achieving high-throughput with minimum hardware resources, this paper proposes a memory-efficient design strategy for a parallel embedded integral image computation engine. Results show that the design achieves nearly 35% reduction in memory for common HD video.

Image fusion using multivariate and multidimensional EMD

2014 IEEE International Conference on Image Processing (ICIP), 2014

We present a novel methodology for the fusion of multiple (two or more) images using the multivar... more We present a novel methodology for the fusion of multiple (two or more) images using the multivariate extension of empirical mode decomposition (MEMD). Empirical mode decomposition (EMD) is a data-driven method which decomposes input data into its intrinsic oscillatory modes, known as intrinsic mode functions (IMFs), without making a priori assumptions regarding the data. We show that the multivariate and multidimensional extensions of EMD are suitable for image fusion purposes. We further demonstrate that while multidimensional extensions, by design, may seem more appropriate for tasks related to image processing, the proposed multivariate extension outperforms these in image fusion applications owing to its mode-alignment property for IMFs. Case studies involving multi-focus image fusion and pan-sharpening of multi-spectral images are presented to demonstrate the effectiveness of the proposed method.

User Tracking Methods for Augmented Reality

International Journal of Computer Theory and Engineering, 2013

ABSTRACT Augmented reality has been an active area of research for the last two decades or so. Th... more ABSTRACT Augmented reality has been an active area of research for the last two decades or so. This paper presents a comprehensive review of the recent literature on tracking methods used in Augmented Reality applications, both for indoor and outdoor environments. After critical discussion of the methods used for tracking, the paper identifies limitations ofthe state-of-the-art techniques and suggests potential future directions to overcome the bottlenecks.

Rate-constrained data aggregation in power-limited multi-sink wireless sensor networks

2014 International Wireless Communications and Mobile Computing Conference (IWCMC), 2014

Feasibility Conditions for Rate-Constrained Routing in Power-Limited Multichannel WSNs

2011 IEEE Global Telecommunications Conference - GLOBECOM 2011, 2011

... Routing in Power-Limited Multichannel WSNs Samina Ehsan, Bechir Hamdaoui, and Mohsen Guizani ... more

Cross-Layer Aware Routing Approaches for Lifetime Maximization in Rate-Constrained Wireless Sensor Networks

2010 IEEE Global Telecommunications Conference GLOBECOM 2010, 2010

ABSTRACT

Citric acid assisted phytoremediation of cadmium by Brassica napus L

Ecotoxicology and Environmental Safety, 2014

Phytoextraction is an eco-friendly and cost-effective technique for removal of toxins, especially... more Phytoextraction is an eco-friendly and cost-effective technique for removal of toxins, especially heavy metals and metalloids from contaminated soils by the roots of high biomass producing plant species with subsequent transport to aerial parts. Lower metal bioavailability often limits the phytoextraction. Organic chelators can help to improve this biological technique by increasing metal solubility. The aim of the present study was to investigate the possibility of improving the phytoextraction of Cd by the application of citric acid. For this purpose, plants were grown in hydroponics under controlled conditions. Results indicated that Cd supply significantly decreased the plant growth, biomass, pigments, photosynthetic characteristics and protein contents which were accompanied by a significant increase in Cd concentration, hydrogen peroxide (H 2 O 2 ), electrolyte leakage, malondialdehyde (MDA) accumulation and decrease in antioxidant capacity. The effects were dose dependent with obvious effects at higher Cd concentration. Application of CA significantly enhanced Cd uptake and its accumulation in plant roots, stems and leaves. Citric acid alleviated Cd toxicity by increasing plant biomass and photosynthetic and growth parameters alone and in combination with Cd and by reducing oxidative stress as observed by reduction in MDA and H 2 O 2 production and decreased electrolyte leakage induced by Cd stress. Application of CA also enhanced the antioxidant enzymes activity alone and under Cd stress. Thus, the data indicate that exogenous CA application can increase Cd uptake and minimize Cd stress in plants and may be beneficial in accelerating the phytoextraction of Cd through hyper-accumulating plants such as Brassica napus L.

Analysis of Interest Point Distribution in SURF Octaves

ijcte.org

Abstract—Speeded-Up Robust Features (SURF) is a state-of-the-art, scale-and rotation-invariant fe... more

Radio and Medium Access Contention Aware Routing for Lifetime Maximization in Multichannel Sensor Networks

IEEE Transactions on Wireless Communications, 2000

ABSTRACT

Analytic Bounds on Data Loss Rates in Mostly-Covered Mobile DTNs

IEEE Transactions on Wireless Communications, 2000

ABSTRACT

An Algorithm for the Contextual Adaption of SURF Octave Selection With Good Matching Performance: Best Octaves

IEEE Transactions on Image Processing, 2000

Speeded-Up Robust Features is a feature extraction algorithm designed for real-time execution, al... more Speeded-Up Robust Features is a feature extraction algorithm designed for real-time execution, although this is rarely achievable on low-power hardware such as that in mobile robots. One way to reduce the computation is to discard some of the scale-space octaves, and previous research has simply discarded the higher octaves. This paper shows that this approach is not always the most sensible and presents an algorithm for choosing which octaves to discard based on the properties of the imagery. Results obtained with this best octaves algorithm show that it is able to achieve a significant reduction in computation without compromising matching performance.

Improved repeatability measures for evaluating performance of feature detectors

Electronics Letters, 2010

The most frequently employed measure for performance characterization of local feature detectors ... more The most frequently employed measure for performance characterization of local feature detectors is repeatability, but it has been observed that this does not necessarily mirror actual performance. In this letter, improved repeatability formulations are presented which correlate much better with the true performance of feature detectors. Comparative results for several state-of-the-art feature detectors are presented using these measures; it is found that Hessian-based detectors are generally superior at identifying features when images are subject to various geometric and photometric transformations.

Tracking Methods for Augmented Reality

... Erkan Bostanci, Nadia Kanwal, Shoaib Ehsan, Adrian F. Clark School of Computer Science and El... more

Node failure detection and path repairing scheme in virtual circuit routing algorithm for wireless ad hoc micro sensor networks

… , 2005. Proceedings of …, 2005

Routing algorithms have shown their importance in the power aware wireless micro-sensor networks.... more Routing algorithms have shown their importance in the power aware wireless micro-sensor networks. In this paper, we present the improved virtuial circulit routing algorithm (IVCRA) implemented in temperatuire sensor application developed by tus. We introduce a method to detect node failure and then to repair the path to routte the data pack-et safely to base station. We verified it by simulating in TOSSIM and then implementing on real motes network. The motes are from Berkeley USA and are being operated by using TinyOS-operating system and nesC language. Energy analysis shows that IVCRA is energy efficient. For IVCRA, we then include the packet size recommended by Zigbee/IEEE 802.15.4 standard, an emerging standard for wireless sensor networks, along with ftatures of its Network Layer.

Morphological, Physiological, and Biochemical Changes in Vitis Genotypes in Response to Photoperiod Regimes

American Journal of Enology and Viticulture, 2013

CITATIONS 16 READS 906 6 authors, including: Some of the authors of this publication are also wor... more

Data Loss Modeling and Analysis in Partially-Covered Delay-Tolerant Networks

2011 Proceedings of 20th International Conference on Computer Communications and Networks (ICCCN), 2011

... Kyle Bradford, Max Brugger, Samina Ehsan, Bechir Hamdaoui, Yevgeniy Kovchegov ... The main co... more

Evaluating the angular sensitivity of corner detectors

2011 IEEE International Conference on Virtual Environments, Human-Computer Interfaces and Measurement Systems Proceedings, 2011

Several popular corner detectors were evaluated on imagery containing corners with a variety of i... more Several popular corner detectors were evaluated on imagery containing corners with a variety of internal angles. Even in a noise-free environment, differences in performance were found. A null hypothesis approach was taken in evaluating whether these performance differences were significant, taking into account correctly the size of the dataset and the number of discrepancies. It was found that some of these performance differences are statistically significant, allowing recommendations to be made regarding which detectors should be used when a problem has corners of known internal angles.

Dynamically sampled multivariate empirical mode decomposition

Electronics Letters, 2015

Measuring the Coverage of Interest Point Detectors

Lecture Notes in Computer Science, 2011

Repeatability is widely used as an indicator of the performance of an image feature detector but,... more Repeatability is widely used as an indicator of the performance of an image feature detector but, although useful, it does not convey all the information that is required to describe performance. This paper explores the spatial distribution of interest points as an alternative indicator of performance, presenting a metric that is shown to concur with visual assessments. This metric is then extended to provide a measure of complementarity for pairs of detectors. Several state-of-the-art detectors are assessed, both individually and in combination. It is found that Scale Invariant Feature Operator (SFOP) is dominant, both when used alone and in combination with other detectors.

A statistical approach for comparing the performances of corner detectors

Proceedings of 2011 IEEE Pacific Rim Conference on Communications, Computers and Signal Processing, 2011

Corner detectors are widely used in computer vision. This paper assesses several state-of-the-art... more Corner detectors are widely used in computer vision. This paper assesses several state-of-the-art corner detectors in terms of overall performance and the internal angles of corners using simple geometric shapes. This assessment is carried out using a statistically-valid null hypothesis approach, not previously used in computer vision. It is found that there are statistically significant differences in performance. Moreover, the null hypothesis approach is easy to use in comparing vision techniques.

Memory-Efficient Design Strategy for a Parallel Embedded Integral Image Computation Engine

2011 Irish Machine Vision and Image Processing Conference, 2011

ABSTRACT In embedded vision systems, parallel computation of the integral image presents several ... more ABSTRACT In embedded vision systems, parallel computation of the integral image presents several design challenges in terms of hardware resources, speed and power consumption. Although recursive equations significantly reduce the number of operations for computing the integral image, the required internal memory becomes prohibitively large for an embedded integral image computation engine for increasing image sizes. With the objective of achieving high-throughput with minimum hardware resources, this paper proposes a memory-efficient design strategy for a parallel embedded integral image computation engine. Results show that the design achieves nearly 35% reduction in memory for common HD video.

Image fusion using multivariate and multidimensional EMD

2014 IEEE International Conference on Image Processing (ICIP), 2014

We present a novel methodology for the fusion of multiple (two or more) images using the multivar... more We present a novel methodology for the fusion of multiple (two or more) images using the multivariate extension of empirical mode decomposition (MEMD). Empirical mode decomposition (EMD) is a data-driven method which decomposes input data into its intrinsic oscillatory modes, known as intrinsic mode functions (IMFs), without making a priori assumptions regarding the data. We show that the multivariate and multidimensional extensions of EMD are suitable for image fusion purposes. We further demonstrate that while multidimensional extensions, by design, may seem more appropriate for tasks related to image processing, the proposed multivariate extension outperforms these in image fusion applications owing to its mode-alignment property for IMFs. Case studies involving multi-focus image fusion and pan-sharpening of multi-spectral images are presented to demonstrate the effectiveness of the proposed method.

User Tracking Methods for Augmented Reality

International Journal of Computer Theory and Engineering, 2013

ABSTRACT Augmented reality has been an active area of research for the last two decades or so. Th... more ABSTRACT Augmented reality has been an active area of research for the last two decades or so. This paper presents a comprehensive review of the recent literature on tracking methods used in Augmented Reality applications, both for indoor and outdoor environments. After critical discussion of the methods used for tracking, the paper identifies limitations ofthe state-of-the-art techniques and suggests potential future directions to overcome the bottlenecks.

Rate-constrained data aggregation in power-limited multi-sink wireless sensor networks

2014 International Wireless Communications and Mobile Computing Conference (IWCMC), 2014

Feasibility Conditions for Rate-Constrained Routing in Power-Limited Multichannel WSNs

2011 IEEE Global Telecommunications Conference - GLOBECOM 2011, 2011

... Routing in Power-Limited Multichannel WSNs Samina Ehsan, Bechir Hamdaoui, and Mohsen Guizani ... more

Cross-Layer Aware Routing Approaches for Lifetime Maximization in Rate-Constrained Wireless Sensor Networks

2010 IEEE Global Telecommunications Conference GLOBECOM 2010, 2010

ABSTRACT

Citric acid assisted phytoremediation of cadmium by Brassica napus L

Ecotoxicology and Environmental Safety, 2014

Phytoextraction is an eco-friendly and cost-effective technique for removal of toxins, especially... more Phytoextraction is an eco-friendly and cost-effective technique for removal of toxins, especially heavy metals and metalloids from contaminated soils by the roots of high biomass producing plant species with subsequent transport to aerial parts. Lower metal bioavailability often limits the phytoextraction. Organic chelators can help to improve this biological technique by increasing metal solubility. The aim of the present study was to investigate the possibility of improving the phytoextraction of Cd by the application of citric acid. For this purpose, plants were grown in hydroponics under controlled conditions. Results indicated that Cd supply significantly decreased the plant growth, biomass, pigments, photosynthetic characteristics and protein contents which were accompanied by a significant increase in Cd concentration, hydrogen peroxide (H 2 O 2 ), electrolyte leakage, malondialdehyde (MDA) accumulation and decrease in antioxidant capacity. The effects were dose dependent with obvious effects at higher Cd concentration. Application of CA significantly enhanced Cd uptake and its accumulation in plant roots, stems and leaves. Citric acid alleviated Cd toxicity by increasing plant biomass and photosynthetic and growth parameters alone and in combination with Cd and by reducing oxidative stress as observed by reduction in MDA and H 2 O 2 production and decreased electrolyte leakage induced by Cd stress. Application of CA also enhanced the antioxidant enzymes activity alone and under Cd stress. Thus, the data indicate that exogenous CA application can increase Cd uptake and minimize Cd stress in plants and may be beneficial in accelerating the phytoextraction of Cd through hyper-accumulating plants such as Brassica napus L.

Analysis of Interest Point Distribution in SURF Octaves

ijcte.org

Abstract—Speeded-Up Robust Features (SURF) is a state-of-the-art, scale-and rotation-invariant fe... more

Radio and Medium Access Contention Aware Routing for Lifetime Maximization in Multichannel Sensor Networks

IEEE Transactions on Wireless Communications, 2000

ABSTRACT

Analytic Bounds on Data Loss Rates in Mostly-Covered Mobile DTNs

IEEE Transactions on Wireless Communications, 2000

ABSTRACT

An Algorithm for the Contextual Adaption of SURF Octave Selection With Good Matching Performance: Best Octaves

IEEE Transactions on Image Processing, 2000

Speeded-Up Robust Features is a feature extraction algorithm designed for real-time execution, al... more Speeded-Up Robust Features is a feature extraction algorithm designed for real-time execution, although this is rarely achievable on low-power hardware such as that in mobile robots. One way to reduce the computation is to discard some of the scale-space octaves, and previous research has simply discarded the higher octaves. This paper shows that this approach is not always the most sensible and presents an algorithm for choosing which octaves to discard based on the properties of the imagery. Results obtained with this best octaves algorithm show that it is able to achieve a significant reduction in computation without compromising matching performance.

Improved repeatability measures for evaluating performance of feature detectors

Electronics Letters, 2010

The most frequently employed measure for performance characterization of local feature detectors ... more The most frequently employed measure for performance characterization of local feature detectors is repeatability, but it has been observed that this does not necessarily mirror actual performance. In this letter, improved repeatability formulations are presented which correlate much better with the true performance of feature detectors. Comparative results for several state-of-the-art feature detectors are presented using these measures; it is found that Hessian-based detectors are generally superior at identifying features when images are subject to various geometric and photometric transformations.

Tracking Methods for Augmented Reality

... Erkan Bostanci, Nadia Kanwal, Shoaib Ehsan, Adrian F. Clark School of Computer Science and El... more

Node failure detection and path repairing scheme in virtual circuit routing algorithm for wireless ad hoc micro sensor networks

… , 2005. Proceedings of …, 2005

Routing algorithms have shown their importance in the power aware wireless micro-sensor networks.... more Routing algorithms have shown their importance in the power aware wireless micro-sensor networks. In this paper, we present the improved virtuial circulit routing algorithm (IVCRA) implemented in temperatuire sensor application developed by tus. We introduce a method to detect node failure and then to repair the path to routte the data pack-et safely to base station. We verified it by simulating in TOSSIM and then implementing on real motes network. The motes are from Berkeley USA and are being operated by using TinyOS-operating system and nesC language. Energy analysis shows that IVCRA is energy efficient. For IVCRA, we then include the packet size recommended by Zigbee/IEEE 802.15.4 standard, an emerging standard for wireless sensor networks, along with ftatures of its Network Layer.

Morphological, Physiological, and Biochemical Changes in Vitis Genotypes in Response to Photoperiod Regimes

American Journal of Enology and Viticulture, 2013

CITATIONS 16 READS 906 6 authors, including: Some of the authors of this publication are also wor... more