28 results match your criteria multi-path propagation

  • Page 1 of 1

Suitability of NB-IoT for Indoor Industrial Environment: A Survey and Insights.

Sensors (Basel) 2021 Aug 5;21(16). Epub 2021 Aug 5.

James Watt School of Engineering, University of Glasgow, Glasgow G12 8QQ, UK.

The Internet of Things (IoT) and its applications in industrial settings are set to bring in the fourth industrial revolution. The industrial environment consisting of high profile manufacturing plants and a variety of equipment is inherently characterized by high reflectiveness, causing significant multi-path components that affect the propagation of wireless communications-a challenge among others that needs to be resolved. This paper provides a detailed insight into Narrow-Band IoT (NB-IoT), Industrial IoT (IIoT), and Wireless Sensor Networks (WSN) within the context of indoor industrial environments. Read More

View Article and Full-Text PDF

Concurrent Modified Constant Modulus Algorithm and Decision Directed Scheme With Barzilai-Borwein Method.

Front Neurorobot 2021 10;15:699221. Epub 2021 Jun 10.

Guangdong Shenglu Telecommunication Tech. Co., Ltd, Foshan, China.

At present, in robot technology, remote control of robot is realized by wireless communication technology, and data anti-interference in wireless channel becomes a very important part. Any wireless communication system has an inherent multi-path propagation problem, which leads to the expansion of generated symbols on a time scale, resulting in symbol overlap and Inter-symbol Interference (ISI). ISI in the signal must be removed and the signal restores to its original state at the time of transmission or becomes as close to it as possible. Read More

View Article and Full-Text PDF

Ordered multi-path propagation for vessel centerline extraction.

Phys Med Biol 2021 Jul 19;66(15). Epub 2021 Jul 19.

Laboratory of Beijing Engineering Research Center of Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, People's Republic of China.

Vessel centerline extraction from x-ray angiography images is essential for vessel structure analysis in the diagnosis of coronary artery disease. However, complete and continuous centerline extraction remains a challenging task due to image noise, poor contrast, and complexity of vessel structure. Thus, an iterative multi-path search framework for automatic vessel centerline extraction is proposed. Read More

View Article and Full-Text PDF

Impact of industrial environments on visible light communication.

Opt Express 2021 May;29(11):16087-16104

Visible-light communication is a promising technology for industrial environments. However, a variety of physical effects may influence the communication quality in this potentially harsh environment: Dust and other particles lead to increased attenuation. Artificial light sources and industrial processes, such as grinding and welding, cause optical cross-talk. Read More

View Article and Full-Text PDF

Investigating Master-Slave Architecture for Underwater Wireless Sensor Network.

Sensors (Basel) 2021 Apr 25;21(9). Epub 2021 Apr 25.

Department of Computer Systems Engineering, University of Engineering and Technology Peshawar, Peshawar 25000, Pakistan.

A significant increase has been observed in the use of Underwater Wireless Sensor Networks (UWSNs) over the last few decades. However, there exist several associated challenges with UWSNs, mainly due to the nodes' mobility, increased propagation delay, limited bandwidth, packet duplication, void holes, and Doppler/multi-path effects. To address these challenges, we propose a protocol named "An Efficient Routing Protocol based on Master-Slave Architecture for Underwater Wireless Sensor Network (ERPMSA-UWSN)" that significantly contributes to optimizing energy consumption and data packet's long-term survival. Read More

View Article and Full-Text PDF

Induced Magnetic Field-Based Indoor Positioning System for Underwater Environments.

Sensors (Basel) 2021 Mar 22;21(6). Epub 2021 Mar 22.

Embedded Intelligence, German Research Center for Artificial Intelligence (DFKI), 67663 Kaiserslautern, Germany.

Autonomous underwater vehicles (AUV) are seen as an emerging technology for maritime exploration but are still restricted by the availability of short range, accurate positioning methods necessary, e.g., when docking remote assets. Read More

View Article and Full-Text PDF

Sim-to-Real: Employing ultrasonic guided wave digital surrogates and transfer learning for damage visualization.

Ultrasonics 2021 Mar 11;111:106338. Epub 2020 Dec 11.

Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL 32611, USA. Electronic address:

Wavefield imaging is a powerful visualization tool in nondestructive evaluation for studying ultrasonic wave propagation and its interactions with damage. To isolate and study damage scattering, damage-free baseline data is often subtracted from a wavefield. This is often necessary because the damage wavefield can be orders of magnitude weaker than the incident waves. Read More

View Article and Full-Text PDF

Indoor channel modeling for continuous variable quantum key distribution in the terahertz band.

Opt Express 2020 Oct;28(22):32386-32402

Continuous-variable quantum key distribution (CVQKD) in an indoor scenario can provide secure wireless access for practical short-distance communications with high rates. However, a suitable channel model for implementing the indoor CVQKD system has not been considered before. Here, we establish an indoor channel model to show the feasibility of CVQKD in terahertz (THz) band. Read More

View Article and Full-Text PDF
October 2020

Locating Mine Microseismic Events in a 3D Velocity Model through the Gaussian Beam Reverse-Time Migration Technique.

Sensors (Basel) 2020 May 8;20(9). Epub 2020 May 8.

State Key Laboratory of Coal Mine Disaster Dynamics and Control, School of Resource and Safety Engineering, Chongqing University, Chongqing 400044, China.

Microseismic (MS) source location is a fundamental and critical task in mine MS monitoring. The traditional ray tracing-based location method can be easily affected by many factors, such as multi-ray path effects, waveform focusing and defocusing of wavefield propagation, and low picking precision of seismic phase arrival. By contrast, the Gaussian beam reverse-time migration (GBRTM) location method can effectively and correctly model the influences of multi-path effects and wavefield focusing and defocusing in complex 3D media, and it takes advantages of the maximum energy focusing point as the source location with the autocorrelation imaging condition, which drastically reduces the requirements of signal-to-noise ratio (SNR) and picking accuracy of P-wave arrival. Read More

View Article and Full-Text PDF

FMCW Laser Fuze Multiple Scattering Model and Accurate Fixed-Distance Algorithm in a Smoke Environment.

Sensors (Basel) 2020 May 3;20(9). Epub 2020 May 3.

School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China.

In a smoke environment, suspended particles can scatter and absorb laser photons, making target echo signals extremely weak and difficult to extract and identify, which causes obvious difficulty in fixed-distance of laser fuze. In this paper, the multiple scattering model of frequency-modulated-continuous-wave (FMCW) laser fuze in a smoke environment was established. This model simulates multi-path propagation and multiple scattering of photons. Read More

View Article and Full-Text PDF

Environmental and operational conditions effects on Lamb wave based structural health monitoring systems: A review.

Ultrasonics 2020 Jul 2;105:106114. Epub 2020 Mar 2.

State Key Laboratory of Structural Analysis for Industry Equipments, School of Aeronautics and Astronautics, Dalian University of Technology, Dalian 116024, Liaoning, China. Electronic address:

Lamb wave is widely recognized as one of the most encouraging tools for structural health monitoring (SHM) systems. In spite of many favourable characteristics of Lamb wave for SHM, real-world application of these systems is still quite limited. Beside the complexities derived from multi-modal, dispersive and multi-path characteristics of Lamb waves, one of the main challenges in Lamb wave based SHM is sensitivity of these systems to environmental and operational conditions (EOCs) parameters. Read More

View Article and Full-Text PDF

An Approach to Frequency Selectivity in an Urban Environment by Means of Multi-Path Acoustic Channel Analysis.

Sensors (Basel) 2019 Jun 21;19(12). Epub 2019 Jun 21.

Grup de recerca en Tecnologies Mèdia (GTM), La Salle, Universitat Ramon Llull, c/Quatre Camins, 30, 08022 Barcelona, Spain.

The improvement of quality of life in the framework of the smart city paradigm cannot be limited to a set of objective measures carried out over several critical parameters (e.g., noise or air pollution). Read More

View Article and Full-Text PDF

An Efficient Multi-Path Multitarget Tracking Algorithm for Over-The-Horizon Radar.

Sensors (Basel) 2019 Mar 20;19(6). Epub 2019 Mar 20.

Department of Electronic Systems Engineering, Hanyang University, Ansan 15588, Korea.

In target tracking environments using over-the-horizon radar (OTHR), one target may generate multiple detections through different signal propagation paths. Trackers need to jointly handle the uncertainties stemming from both measurement origin and measurement path. Traditional multitarget tracking algorithms suffer from high computational loads in such environments since they need to enumerate all possible joint measurement-to-track assignments considering the measurements paths unless they employ some approximations regarding the measurements and their corresponding paths. Read More

View Article and Full-Text PDF

Demodulation of Chaos Phase Modulation Spread Spectrum Signals Using Machine Learning Methods and Its Evaluation for Underwater Acoustic Communication.

Sensors (Basel) 2018 Dec 1;18(12). Epub 2018 Dec 1.

LE2I EA7508, Université Bourgogne Franche-Comté, 21078 Dijon, France.

The chaos phase modulation sequences consist of complex sequences with a constant envelope, which has recently been used for direct-sequence spread spectrum underwater acoustic communication. It is considered an ideal spreading code for its benefits in terms of large code resource quantity, nice correlation characteristics and high security. However, demodulating this underwater communication signal is a challenging job due to complex underwater environments. Read More

View Article and Full-Text PDF
December 2018

Wave propagation through disordered media without backscattering and intensity variations.

Light Sci Appl 2017 Sep 8;6(9):e17035. Epub 2017 Sep 8.

Institute for Theoretical Physics, Vienna University of Technology (TU-Wien), Vienna 1040, Austria.

A fundamental manifestation of wave scattering in a disordered medium is the highly complex intensity pattern the waves acquire due to multi-path interference. Here we show that these intensity variations can be entirely suppressed by adding disorder-specific gain and loss components to the medium. The resulting constant-intensity waves in such non-Hermitian scattering landscapes are free of any backscattering and feature perfect transmission through the disorder. Read More

View Article and Full-Text PDF
September 2017

M-SAC-VLADNet: A Multi-Path Deep Feature Coding Model for Visual Classification.

Entropy (Basel) 2018 May 4;20(5). Epub 2018 May 4.

The National Engineering Technology Research Center for Mobile Ultrasonic Detection, School of Electronics and Information Engineering, South China University of Technology, Guangzhou 510641, China.

Vector of locally aggregated descriptor (VLAD) coding has become an efficient feature coding model for retrieval and classification. In some recent works, the VLAD coding method is extended to a deep feature coding model which is called NetVLAD. NetVLAD improves significantly over the original VLAD method. Read More

View Article and Full-Text PDF

Mobile Sinks Assisted Geographic and Opportunistic Routing Based Interference Avoidance for Underwater Wireless Sensor Network.

Sensors (Basel) 2018 Apr 2;18(4). Epub 2018 Apr 2.

Cameron Library, University of Alberta, Edmonton, AB T6G 2J8, Canada.

The distinctive features of acoustic communication channel-like high propagation delay, multi-path fading, quick attenuation of acoustic signal, etc. limit the utilization of underwater wireless sensor networks (UWSNs). The immutable selection of forwarder node leads to dramatic death of node resulting in imbalanced energy depletion and void hole creation. Read More

View Article and Full-Text PDF

Direct Position Determination of Unknown Signals in the Presence of Multipath Propagation.

Sensors (Basel) 2018 Mar 17;18(3). Epub 2018 Mar 17.

National Digital Switching System Engineering and Technological Research Center, Zhengzhou 450002, China.

A novel geolocation architecture, termed "Multiple Transponders and Multiple Receivers for Multiple Emitters Positioning System (MTRE)" is proposed in this paper. Existing Direct Position Determination (DPD) methods take advantage of a rather simple channel assumption (line of sight channels with complex path attenuations) and a simplified MUltiple SIgnal Classification (MUSIC) algorithm cost function to avoid the high dimension searching. We point out that the simplified assumption and cost function reduce the positioning accuracy because of the singularity of the array manifold in a multi-path environment. Read More

View Article and Full-Text PDF

LOCALI: Calibration-Free Systematic Localization Approach for Indoor Positioning.

Sensors (Basel) 2017 May 25;17(6). Epub 2017 May 25.

Department of Information and Communication Engineering, Yeungnam University, Gyeongsan 38541, Korea.

Recent advancements in indoor positioning systems are based on infrastructure-free solutions, aimed at improving the location accuracy in complex indoor environments without the use of specialized resources. A popular infrastructure-free solution for indoor positioning is a calibration-based positioning, commonly known as fingerprinting. Fingerprinting solutions require extensive and error-free surveys of environments to build radio-map databases, which play a key role in position estimation. Read More

View Article and Full-Text PDF

Pre-clinical investigations of multi-path propagation in transcranial Doppler ultrasound flow phantom.

Annu Int Conf IEEE Eng Med Biol Soc 2016 Aug;2016:3586-3589

There are various practical situations in medical applications when pre-clinical investigations must be performed using a simulation environment or test bench prior to human studies. One example is the analysis of propagation channels in Transcanial Doppler (TCD) ultrasound (US), a signal processing challenge requiring the analysis of data from US waves scattered in three dimensions (3D). When examining the effects of scatterers in such channels, it is common to use a data acquisition test bench and a Doppler flow phantom. Read More

View Article and Full-Text PDF

Experimental validation of wireless communication with chaos.

Chaos 2016 Aug;26(8):083117

Institute for Complex System and Mathematical Biology, SUPA, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom.

The constraints of a wireless physical media, such as multi-path propagation and complex ambient noises, prevent information from being communicated at low bit error rate. Surprisingly, it has only recently been shown that, from a theoretical perspective, chaotic signals are optimal for communication. It maximises the receiver signal-to-noise performance, consequently minimizing the bit error rate. Read More

View Article and Full-Text PDF

A wall-less poly(vinyl alcohol) cryogel flow phantom with accurate scattering properties for transcranial Doppler ultrasound propagation channels analysis.

Annu Int Conf IEEE Eng Med Biol Soc 2015 Aug;2015:2709-12

Medical phantoms are frequently required to verify image and signal processing systems, and are often used to support algorithm development for a wide range of imaging and blood flow assessments. A phantom with accurate scattering properties is a crucial requirement when assessing the effects of multi-path propagation channels during the development of complex signal processing techniques for Transcranial Doppler (TCD) ultrasound. The simulation of physiological blood flow in a phantom with tissue and blood equivalence can be achieved using a variety of techniques. Read More

View Article and Full-Text PDF

Reverberation clutter from subcutaneous tissue layers: simulation and in vivo demonstrations.

Ultrasound Med Biol 2014 Apr 14;40(4):714-26. Epub 2014 Feb 14.

Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA.

The degradation of ultrasonic image quality is typically attributed to aberration and reverberation. Although the sources and impact of aberration are well understood, very little is known about the source and impact of image degradation caused by reverberation. Reverberation is typically associated with multiple reflections at two interfaces along the same propagation path, as with the arterial wall or a metal sphere. Read More

View Article and Full-Text PDF

Shallow-water acoustic tomography from angle measurements instead of travel-time measurements.

J Acoust Soc Am 2013 Oct;134(4):EL373-9

Unité Mixte de Recherche 5216 CNRS, Grenoble Institut National Polytechnique, Université Joseph Fourier, Université Stendhal, 11 Rue des Mathématiques, Grenoble Campus, BP46, F - 38402 Saint Martin d'Hères Cedex, France

For shallow-water waveguides and mid-frequency broadband acoustic signals, ocean acoustic tomography (OAT) is based on the multi-path aspect of wave propagation. Using arrays in emission and reception and advanced array processing, every acoustic arrival can be isolated and matched to an eigenray that is defined not only by its travel time but also by its launch and reception angles. Classically, OAT uses travel-time variations to retrieve sound-speed perturbations; this assumes very accurate source-to-receiver clock synchronization. Read More

View Article and Full-Text PDF
October 2013

A stratified acoustic model accounting for phase shifts for underwater acoustic networks.

Sensors (Basel) 2013 May 13;13(5):6183-203. Epub 2013 May 13.

Department of Electronic Engineering, Tsinghua University, Beijing 100084, China.

Accurate acoustic channel models are critical for the study of underwater acoustic networks. Existing models include physics-based models and empirical approximation models. The former enjoy good accuracy, but incur heavy computational load, rendering them impractical in large networks. Read More

View Article and Full-Text PDF

Blind location and separation of callers in a natural chorus using a microphone array.

J Acoust Soc Am 2009 Aug;126(2):895-910

Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, 1308 W. Main Street, Urbana, IL 61801, USA.

Male frogs and toads call in dense choruses to attract females. Determining the vocal interactions and spatial distribution of the callers is important for understanding acoustic communication in such assemblies. It has so far proved difficult to simultaneously locate and recover the vocalizations of individual callers. Read More

View Article and Full-Text PDF

Adaptive microphone array for unknown desired speaker's transfer function.

J Acoust Soc Am 2007 Aug;122(2):EL44-9

Faculty of Technical Sciences, University of Novi Sad, Novi Sad, Serbia.

The main drawback of minimum variance distortionless response (MVDR) beamformer is the cancellation of the desired speech signal and its degradation in multi-path wave propagation environment. To make the adaptive algorithm robust against room reverberation and to prevent desired signal cancellation an estimation of unknown desired speaker's transfer function was proposed. The estimation is based on the signal and the interference covariance matrices. Read More

View Article and Full-Text PDF

Coherent optical communication using polarization multiple-input-multiple-output.

Authors:
Yan Han Guifang Li

Opt Express 2005 Sep;13(19):7527-34

Polarization-division multiplexed (PDM) optical signals can potentially be demultiplexed by coherent detection and digital signal processing without using optical dynamic polarization control at the receiver. In this paper, we show that optical communications using PDM is analogous to wireless communications using multiple-input-multiple-output (MIMO) antennae and thus algorithms for channel estimation in wireless MIMO can be ready applied to optical polarization MIMO (PMIMO). Combined with frequency offset and phase estimation algorithms, simulations show that PDM quadrature phase-shift keying signals can be coherently detected by the proposed scheme using commercial semiconductor lasers while no optical phase locking and polarization control are required. Read More

View Article and Full-Text PDF
September 2005
  • Page 1 of 1