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This paper introduces an innovative imaging method using reconfigurable intelligent surfaces (RISs) by combining radar coincidence imaging (RCI) and computational imaging techniques. In the proposed framework, RISs simultaneously redirect…

Signal Processing · Electrical Eng. & Systems 2025-07-11 Kavian Zirak , Mohammadreza F. Imani

High-resolution observations of dynamic phenomena give insight into properties and processes that govern the low solar atmosphere. We present the analysis of jet-like phenomena emanating from a penumbral foot-point in active region (AR)…

Solar and Stellar Astrophysics · Physics 2020-10-09 Llŷr Dafydd Humphries , Erwin Verwichte , David Kuridze , Huw Morgan

We propose a new iris presentation attack detection method using three-dimensional features of an observed iris region estimated by photometric stereo. Our implementation uses a pair of iris images acquired by a common commercial iris…

Computer Vision and Pattern Recognition · Computer Science 2018-11-20 Adam Czajka , Zhaoyuan Fang , Kevin W. Bowyer

We report on the first Interface Region Imaging Spectrograph (IRIS) study of cool transition region loops. This class of loops has received little attention in the literature. A cluster of such loops was observed on the solar disk in active…

Solar and Stellar Astrophysics · Physics 2015-09-09 Zhenghua Huang , Lidong Xia , Bo Li , Maria S. Madjarska

In this paper, we investigate the performance of a reconfigurable intelligent surface (RIS) assisted large-scale network by characterizing the coverage probability and the average achievable rate using stochastic geometry. Considering the…

Signal Processing · Electrical Eng. & Systems 2022-08-19 Tianxiong Wang , Gaojie Chen , Mihai-Alin Badiu , Justin P. Coon

Loops are one of the fundamental structures that trace the geometry of the magnetic field in the solar atmosphere. Their evolution and dynamics provide a crucial proxy for studying how the magnetized structures are formed and heated in the…

Solar and Stellar Astrophysics · Physics 2020-01-08 Zhenghua Huang , Bo Li , Lidong Xia , Mijie Shi , Hui Fu , Zhenyong Hou

Solar spicules have eluded modelers and observers for decades. Since the discovery of the more energetic type II, spicules have become a heated topic but their contribution to the energy balance of the low solar atmosphere remains unknown.…

The Interface Region Imaging Spectrograph (IRIS) reveals numerous small-scale (sub-arcsecond) brightenings that appear as bright dots sparkling the solar transition region in active regions. Here, we report a statistical study on these…

Solar and Stellar Astrophysics · Physics 2018-03-23 Zhenyong Hou , Zhenghua Huang , Lidong Xia , Bo Li , Maria S. Madjarska , Hui Fu

Iris recognition has drawn a lot of attention since the mid-twentieth century. Among all biometric features, iris is known to possess a rich set of features. Different features have been used to perform iris recognition in the past. In this…

Computer Vision and Pattern Recognition · Computer Science 2015-07-09 Shervin Minaee , AmirAli Abdolrashidi , Yao Wang

We present sensitivity estimates for point and resolved astronomical sources for the current design of the InfraRed Imaging Spectrograph (IRIS) on the future Thirty Meter Telescope (TMT). IRIS, with TMT's adaptive optics system, will…

Instrumentation and Methods for Astrophysics · Physics 2015-05-19 Shelley A. Wright , Elizabeth J. Barton , James E. Larkin , Anna M. Moore , David Crampton , Luc Simard , IRIS team

The Iris pattern is a unique biological feature for each individual, making it a valuable and powerful tool for human identification. In this paper, an efficient framework for iris recognition is proposed in four steps. (1) Iris…

Computer Vision and Pattern Recognition · Computer Science 2020-09-15 Abolfazl Zargari Khuzani , Najmeh Mashhadi , Morteza Heidari , Donya Khaledyan

Reconfigurable intelligent surfaces (RISs), also known as intelligent reflecting surfaces (IRSs), or large intelligent surfaces (LISs), have received significant attention for their potential to enhance the capacity and coverage of wireless…

Signal Processing · Electrical Eng. & Systems 2021-05-05 Yuanwei Liu , Xiao Liu , Xidong Mu , Tianwei Hou , Jiaqi Xu , Marco Di Renzo , Naofal Al-Dhahir

A systematic search for cosmic gamma-ray bursts (GRBs) and other short hard X-ray events in the archival data from the IBIS/ISGRI telescope of the INTEGRAL observatory over 2003-2018 has been carried out. Seven previously unknown GRBs have…

High Energy Astrophysical Phenomena · Physics 2020-05-26 I. V. Chelovekov , S. A. Grebenev , A. S. Pozanenko , P. Yu. Minaev

The Interface Region Imaging Spectrograph (IRIS) provides spectroscopy and narrow band slit-jaw (SJI) imaging of the solar chromosphere and transition region at unprecedented spatial and temporal resolution. Combined with high-resolution…

Solar and Stellar Astrophysics · Physics 2016-02-03 H. Skogsrud , L. Rouppe van der Voort , B. De Pontieu

The resonance lines of \ion{Si}{4} formed at $\lambda$1394 and 1403 {\AA} are the most critical for the diagnostics of the solar transition region in the observations of the Interface Region Imaging Spectrograph (IRIS). Studying the…

Solar and Stellar Astrophysics · Physics 2020-05-20 Durgesh Tripathi , V. N. Nived , Hiroaki Isobe , J. G. Doyle

Narrow band bursts appear on dynamic spectra from microwave to decametric frequencies as fine structures with very small duration and bandwidth. They are thought to mark small scale magnetic reconnection. We analyzed 27 metric type-IV…

Solar and Stellar Astrophysics · Physics 2016-01-27 C. Bouratzis , A. Hillaris , C. E. Alissandrakis , P. Preka-Papadema , X. Moussas , C. Caroubalos , P. Tsitsipis , A. Kontogeorgos

Antenna array technology enables directional transmission and reception of wireless signals, for communications, localization, and sensing purposes. The signal processing algorithms that underpin this technology began to be developed…

Signal Processing · Electrical Eng. & Systems 2022-03-09 Emil Björnson , Henk Wymeersch , Bho Matthiesen , Petar Popovski , Luca Sanguinetti , Elisabeth de Carvalho

Reconfigurable intelligent surfaces, with their large number of antennas, offer an interesting opportunity for high spatial-resolution imaging. In this paper, we propose a novel RIS-aided integrated imaging and communication system that can…

Signal Processing · Electrical Eng. & Systems 2024-01-30 Hao Luo , Ahmed Alkhateeb

Reconfigurable intelligent surface (RIS)-assisted communication is a key enabling technology for next-generation wireless communication networks, allowing for the reshaping of wireless channels without requiring traditional radio frequency…

Signal Processing · Electrical Eng. & Systems 2025-11-18 Recep Vural , Aymen Khaleel , Ertugrul Basar

Diversity and unpredictability of artifacts potentially presented to an iris sensor calls for presentation attack detection methods that are agnostic to specificity of presentation attack instruments. This paper proposes a method that…

Computer Vision and Pattern Recognition · Computer Science 2020-08-06 Zhaoyuan Fang , Adam Czajka , Kevin W. Bowyer