scholarly journals A small-scale hyperacute compound eye featuring active eye tremor: application to visual stabilization, target tracking, and short-range odometry

2015 ◽  
Vol 10 (2) ◽  
pp. 026002 ◽  
Author(s):  
Fabien Colonnier ◽  
Augustin Manecy ◽  
Raphaël Juston ◽  
Hanspeter Mallot ◽  
Robert Leitel ◽  
...  
Keyword(s):  
Target Tracking ◽  
Short Range ◽  
Compound Eye ◽  
Small Scale ◽  
Visual Stabilization

A Study on Small Scale Associated Gas FLNG Utilizing Small Scale LNG Carriers to Near-By Onshore LNG Plant

2016 ◽  
Author(s):  
X. C. Nguyen ◽  
Komla Miheaye ◽  
Mun-gyu Kim ◽  
Howard Newman ◽  
Dong-hoon Yoo ◽  
...  
Keyword(s):  
Short Range ◽  
Storage Capacity ◽  
Effective Means ◽  
Production Capacity ◽  
Cost Effective ◽  
Oil Fields ◽  
Small Scale ◽  
Associated Gas ◽  
Small Capacity ◽  
Stranded Gas

This study describes a FLNG specifically designed to monetize Associated Gas (AG) of producing oil fields located within convenient distance of an existing LNG Plant or Port with LNG storage facility. Limited production capacity combined with short range small capacity shuttles and limited LNG storage capacity, provide a cost effective means for LNG production. This FLNG is designed to service an existing industry and does not require development of stranded gas discoveries.

scholarly journals Demonstration and uncertainty analysis of synchronised scanning lidar measurements of 2-D velocity fields in a boundary-layer wind tunnel

2017 ◽  
Vol 2 (1) ◽  
pp. 329-341 ◽  
Author(s):  
Marijn Floris van Dooren ◽  
Filippo Campagnolo ◽  
Mikael Sjöholm ◽  
Nikolas Angelou ◽  
Torben Mikkelsen ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Uncertainty Analysis ◽  
Wind Turbine ◽  
Short Range ◽  
Goodness Of Fit ◽  
Wind Tunnels ◽  
Small Scale ◽  
Measurement Technology ◽  
Lidar Measurement ◽  
Hot Wire

Abstract. This paper combines the research methodologies of scaled wind turbine model experiments in wind tunnels with short-range WindScanner lidar measurement technology. The wind tunnel at the Politecnico di Milano was equipped with three wind turbine models and two short-range WindScanner lidars to demonstrate the benefits of synchronised scanning lidars in such experimental surroundings for the first time. The dual-lidar system can provide fully synchronised trajectory scans with sampling timescales ranging from seconds to minutes. First, staring mode measurements were compared to hot-wire probe measurements commonly used in wind tunnels. This yielded goodness of fit coefficients of 0.969 and 0.902 for the 1 Hz averaged u and v components of the wind speed, respectively, validating the 2-D measurement capability of the lidar scanners. Subsequently, the measurement of wake profiles on a line as well as wake area scans were executed to illustrate the applicability of lidar scanning to the measurement of small-scale wind flow effects. An extensive uncertainty analysis was executed to assess the accuracy of the method. The downsides of lidar with respect to the hot-wire probes are the larger measurement probe volume, which compromises the ability to measure turbulence, and the possible loss of a small part of the measurements due to hard target beam reflection. In contrast, the benefits are the high flexibility in conducting both point measurements and area scanning and the fact that remote sensing techniques do not disturb the flow during measuring. The research campaign revealed a high potential for using short-range synchronised scanning lidars to measure the flow around wind turbines in a wind tunnel and increased the knowledge about the corresponding uncertainties.

scholarly journals QoS Enabled Heterogeneous BLE Mesh Networks

2021 ◽  
Vol 10 (2) ◽  
pp. 24
Author(s):  
Subho Shankar Basu ◽  
Mathias Baert ◽  
Jeroen Hoebeke
Keyword(s):  
Traffic Management ◽  
Short Range ◽  
Mesh Networks ◽  
Random Access ◽  
Mesh Network ◽  
Small Scale ◽  
Efficient Management ◽  
Scale Test ◽  
The Cost

Bluetooth Low Energy (BLE) is a widely known short-range wireless technology used for various Internet of Things (IoT) applications. Recently, with the introduction of BLE mesh networks, this short-range barrier of BLE has been overcome. However, the added advantage of an extended range can come at the cost of a lower performance of these networks in terms of latency, throughput and reliability, as the core operation of BLE mesh is based on advertising and packet flooding. Hence, efficient management of the system is required to achieve a good performance of these networks and a smoother functioning in dense scenarios. As the number of configuration points in a standard mesh network is limited, this paper describes a novel set of standard compliant Quality of Service (QoS) extensions for BLE mesh networks. The resulting QoS features enable better traffic management in the mesh network, providing sufficient redundancy to achieve reliability whilst avoiding unnecessary packet flooding to reduce collisions, as well as the prioritization of certain traffic flows and the ability to control end-to-end latencies. The QoS-based system has been implemented and validated in a small-scale BLE mesh network and compared against a setup without any QoS support. The assessment in a small-scale test setup confirms that applying our QoS features can enhance these types of non-scheduled and random access networks in a significant way.

scholarly journals Black carbon aerosol number and mass concentration measurements by picosecond short-range elastic backscatter lidar

2021 ◽  
Author(s):  
Romain Ceolato ◽  
Andres Bedoya-Velasquez ◽  
Frederic Fossard ◽  
Vincent Mouysset ◽  
Lucas Paulien ◽  
...  
Keyword(s):  
Black Carbon ◽  
Cross Sections ◽  
Time Resolution ◽  
Mass Concentration ◽  
Short Range ◽  
Small Scale ◽  
Inversion Method ◽  
Remote Measurement ◽  
Fractal Aggregates ◽  
Black Carbon Aerosol

Abstract Black carbon aerosol emissions are recognized as contributors to global warming and air pollution. There remains, however, a lack of in-situ techniques to remotely quantify black carbon aerosol particles with high range and time resolution. This article presents for the first time, to our knowledge, a direct and contact-free remote measurement of black carbon aerosol number and mass concentration less than ten of meters from the emission source. This is done with a novel picosecond short-range elastic backscatter lidar (PSR-EBL) technique. To address the complexity of retrieving lidar products at short measurement ranges, we apply a forward inversion method featuring radiometric lidar calibration. Our method is based on an extension of a well-established light-scattering model, the Rayleigh-Debye-Gans for Fractal-Aggregates (RDG-FA) theory, which computes an analytical expression for lidar parameters. These parameters are the backscattering cross-sections and the lidar ratio for black carbon fractal aggregates. Using a small-scale Jet A-1 kerosene pool fire, it is shown that our technique can quantify the aerosol number and mass concentration with centimetre range-resolution and millisecond time-resolution.

scholarly journals Deep Learning-Based Ground Target Detection and Tracking for Aerial Photography from UAVs

2021 ◽  
Vol 11 (18) ◽  
pp. 8434
Author(s):  
Kaipeng Wang ◽  
Zhijun Meng ◽  
Zhe Wu
Keyword(s):  
Deep Learning ◽  
Target Tracking ◽  
Target Detection ◽  
Aerial Photography ◽  
Tracking Algorithm ◽  
Aerial Image ◽  
Small Scale ◽  
Detection And Tracking ◽  
Tracking Algorithms ◽  
Ground Target

Target detection and tracking can be widely used in military and civilian scenarios. Unmanned aerial vehicles (UAVs) have high maneuverability and strong concealment, thus they are very suitable for using as a platform for ground target detection and tracking. Most of the existing target detection and tracking algorithms are aimed at conventional targets. Because of the small scale and the incomplete details of the targets in the aerial image, it is difficult to apply the conventional algorithms to aerial photography from UAVs. This paper proposes a ground target image detection and tracking algorithm applied to UAVs using a revised deep learning technology. Aiming at the characteristics of ground targets in aerial images, target detection algorithms and target tracking algorithms are improved. The target detection algorithm is improved to detect small targets on the ground. The target tracking algorithm is designed to recover the target after the target is lost. The target detection and tracking algorithm is verified on the aerial dataset.

scholarly journals Demonstration and uncertainty analysis of synchronised scanning lidar measurements of 2D velocity fields in a boundary-layer wind tunnel

2017 ◽  
Author(s):  
Marijn F. van Dooren ◽  
Filippo Campagnolo ◽  
Mikael Sjöholm ◽  
Nikolas Angelou ◽  
Torben Mikkelsen ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Wind Tunnel ◽  
Uncertainty Analysis ◽  
Wind Turbine ◽  
Short Range ◽  
Goodness Of Fit ◽  
Wind Tunnels ◽  
Small Scale ◽  
Lidar Measurement ◽  
Hot Wire

Abstract. This paper combines the currently relevant research methodologies of scaled wind turbine model experiments in wind tunnels with remote-sensing short-range WindScanner lidar measurement technology. The wind tunnel of the Politecnico di Milano was equipped with three wind turbine models and two short-range WindScanner lidars to demonstrate the benefits of synchronised scanning lidars in such experimental surroundings for the first time. The dual-lidar system can provide fully synchronised trajectory scans with sampling time scales ranging from seconds to minutes. First, staring mode measurements were compared to hot-wire probe measurements commonly used in wind tunnels. This yielded goodness of fit coefficients of 0.969 and 0.902 for the 1 Hz averaged u- and v-components of the wind speed, respectively, validating the 2D measurement capability of the lidar scanners. Subsequently, the measurement of wake profiles on a line as well as wake area scans were executed to illustrate the applicability of lidar scanning to measuring small scale wind flow effects. An extensive uncertainty analysis was executed to assess the accuracy of the method. The downsides of lidar with respect to the hot-wire probes are the larger measurement probe volume and the loss of some measurements due to moving blades. In contrast, the benefits are the high flexibility in conducting both point measurements and area scanning, and the fact that remote sensing techniques do not disturb the flow while measuring. The research campaign revealed a high potential for using short-range synchronised scanning lidars to accurately measure small scale flow structures in a wind tunnel, and increased the knowledge about the corresponding uncertainties.

Ensemble generation strategies for the short-range forecast of flash floods: the 12-13 September 2019 event in Eastern Spain

2020 ◽  
Author(s):  
Alejandro Hermoso ◽  
Victor Homar ◽  
Arnau Amengual
Keyword(s):  
Mediterranean Region ◽  
Short Range ◽  
Dynamical Downscaling ◽  
Mesoscale Model ◽  
Heavy Precipitation ◽  
Ensemble Prediction ◽  
Economic Losses ◽  
Small Scale ◽  
Flash Flooding ◽  
Ensemble Generation

<p>The Mediterranean region is frequently affected by heavy precipitation and flash flooding during the extended warm season. A precise meteorological forecast of socially relevant aspects of these phenomena such as location, timing and intensity is crucial to prevent personal and material losses. However, forecasting these aspects becomes extremely challenging due to small-scale processes involved in the triggering, development and subsequent evolution of convective systems.</p><p> </p><p>On 12 and 13 September 2019 widespread flash flooding caused devastating effects across Murcia and Valencia, eastern Spain. Seven fatalities were reported, hundreds of homes were flooded and economic losses were estimated at 200 M€. The performance of various ensemble generation strategies for short-range convection-permitting ensemble prediction systems (EPS) are evaluated for this episode. Different sources of error are coped by the implemented ensemble generation approaches.  Uncertainty in the initial and lateral boundary conditions uncertainty is sampled in two ways: (i) the dynamical downscaling of the ECMWF global EPS and, (ii) a new tailored breeding technique that accounts for perturbations across the multiple scales of interest for short-range forecasting. Additionally, errors in mesoscale model formulation are encompassed by combining different parameterization schemes and stochastic physics.</p><p> </p><p>This study contributes to the identification of the most relevant sources of uncertainty hampering an accurate spatial and temporal forecasting of heavy precipitation resulting in flash flooding over the Spanish Mediterranean region. These cutting-edge EPS can contribute to implement more reliable and effective hydrometeorological prediction chains with lead times up to 24 h, providing a valuable support to civil protection and emergency management authorities.</p>

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