scholarly journals LaPIV using multigrid warping and proxy regularization

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Yin Yang ◽  
Dominique Heitz
Keyword(s):  
Early Stage ◽  
Image Features ◽  
Velocity Estimation ◽  
Estimation Methods ◽  
Small Scale ◽  
Lagrangian Particle ◽  
Synthetic Datasets ◽  
Eulerian Dynamics ◽  
Particle Images ◽  
Lagrangian Flow

The Lagrangian Particle Image Velocimetry (LAPIV) method was firstly proposed in Yang et al. (2019) as a prototype approach to achieve the goal of accurate and efficient reconstruction of 3D Eulerian velocity field of fluid flow from multi-view particle images. After validating against synthetic datasets, the prototype has already shown significant advantages in revealing more small scale flow structures than other stateof-the-art Eulerian velocity estimation methods, such as TomoPIV (Scarano, 2013) and VIC# (Jeon et al., 2019). However, at this early stage, LAPIV can not be easily applied to other datasets. In the current work, we focus on extending LAPIV to operational search by incorporating several essential and wellestablished paradigms: multi-resolution, warping, and proxy regularization. Recent approaches, Lasinger et al. (2019) and Cornic et al. (2020), function in the same vein as LAPIV, aiming at reconstructs the dense Eulerian volumetric flow directly from multi-view particle-seeded images Another pipeline consists of firstly reconstructing the Lagrangian flow using the Lagrangian Particle Tracking (LPT), then optimally interpolating the Lagrangian flow to Eulerian grids, taking into account the Eulerian dynamics constraints as in Flowfit (Gesemann, 2020) and VIC# (Jeon et al., 2019). If Eulerian flow is required, LAPIV is the preferred approach due to its simplicity and ability to utilize the original rich image features.

scholarly journals A Lightweight Fusion Distillation Network for Image Deblurring and Deraining

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5312
Author(s):  
Yanni Zhang ◽  
Yiming Liu ◽  
Qiang Li ◽  
Jianzhong Wang ◽  
Miao Qi ◽  
...  
Keyword(s):  
Deep Learning ◽  
Image Deblurring ◽  
Image Features ◽  
Image Feature ◽  
Model Complexity ◽  
Small Scale ◽  
Feature Maps ◽  
Learning Framework ◽  
Channel Information ◽  
Scale Spaces

Recently, deep learning-based image deblurring and deraining have been well developed. However, most of these methods fail to distill the useful features. What is more, exploiting the detailed image features in a deep learning framework always requires a mass of parameters, which inevitably makes the network suffer from a high computational burden. We propose a lightweight fusion distillation network (LFDN) for image deblurring and deraining to solve the above problems. The proposed LFDN is designed as an encoder–decoder architecture. In the encoding stage, the image feature is reduced to various small-scale spaces for multi-scale information extraction and fusion without much information loss. Then, a feature distillation normalization block is designed at the beginning of the decoding stage, which enables the network to distill and screen valuable channel information of feature maps continuously. Besides, an information fusion strategy between distillation modules and feature channels is also carried out by the attention mechanism. By fusing different information in the proposed approach, our network can achieve state-of-the-art image deblurring and deraining results with a smaller number of parameters and outperform the existing methods in model complexity.

scholarly journals The Growth of Leaf Lettuce and Bacterial Communities in a Closed Aquaponics System with Catfish

Horticulturae ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 222
Author(s):  
Kenji Yamane ◽  
Yuuki Kimura ◽  
Keita Takahashi ◽  
Isamu Maeda ◽  
Masayuki Iigo ◽  
...  
Keyword(s):  
Plant Growth ◽  
Early Stage ◽  
Amplicon Sequencing ◽  
Small Scale ◽  
Rrna Gene ◽  
Culture Solution ◽  
Beneficial Effects ◽  
Sustainable Cultivation ◽  
Microbial Groups ◽  
Production Period

Aquaponics is a circulating and sustainable system that combines aquaculture and hydroponics and forms a symbiotic relationship between fish, plants, and microorganisms. We hypothesized that feed alone could support plant growth, but the symbiosis with fish adds some beneficial effects on plant growth in aquaponics. In this study, we created three closed culture systems, namely, aquaponics, hydroponics without nitrogen (N) and phosphorus (P), and aquaculture, and added the same amount of feed containing N and P to all the treatments in order to test the hypothesis. Accumulation of NO3− and PO43− was alleviated in aquaponics and hydroponics as a result of plant uptake. Lettuce plants grown in aquaponics grew vigorously until 2 weeks and contained a constant level of N in plants throughout the production period, whereas those in hydroponics grew slowly in the early stage and then vigorously after 2 weeks with a late increment of N concentration. These results suggest that catfish help with the faster decomposition of the feed, but, in hydroponics, feed can be slowly dissolved and decomposed owing to the absence of the fish. The bacterial community structures of the culture solution were investigated using 16S rRNA gene amplicon sequencing. At the class level, Actinobacteria, Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria were the major microbial groups in the solutions. Aquaponics prevented the pollution of tank solution and maintained a higher water quality compared with hydroponics and aquaculture, suggesting that aquaponics is a more sustainable cultivation system even in a small-scale system.

scholarly journals Computational Geometry-Based Surface Reconstruction for Volume Estimation: A Case Study on Magnitude-Frequency Relations for a LiDAR-Derived Rockfall Inventory

2021 ◽  
Vol 10 (3) ◽  
pp. 157
Author(s):  
Paul-Mark DiFrancesco ◽  
David A. Bonneau ◽  
D. Jean Hutchinson
Keyword(s):  
Computational Geometry ◽  
Surface Reconstruction ◽  
Power Law ◽  
Point Cloud ◽  
Point Clouds ◽  
Volume Estimation ◽  
Estimation Methods ◽  
Small Scale ◽  
Reconstruction Methods ◽  
3D Volume

Key to the quantification of rockfall hazard is an understanding of its magnitude-frequency behaviour. Remote sensing has allowed for the accurate observation of rockfall activity, with methods being developed for digitally assembling the monitored occurrences into a rockfall database. A prevalent challenge is the quantification of rockfall volume, whilst fully considering the 3D information stored in each of the extracted rockfall point clouds. Surface reconstruction is utilized to construct a 3D digital surface representation, allowing for an estimation of the volume of space that a point cloud occupies. Given various point cloud imperfections, it is difficult for methods to generate digital surface representations of rockfall with detailed geometry and correct topology. In this study, we tested four different computational geometry-based surface reconstruction methods on a database comprised of 3668 rockfalls. The database was derived from a 5-year LiDAR monitoring campaign of an active rock slope in interior British Columbia, Canada. Each method resulted in a different magnitude-frequency distribution of rockfall. The implications of 3D volume estimation were demonstrated utilizing surface mesh visualization, cumulative magnitude-frequency plots, power-law fitting, and projected annual frequencies of rockfall occurrence. The 3D volume estimation methods caused a notable shift in the magnitude-frequency relations, while the power-law scaling parameters remained relatively similar. We determined that the optimal 3D volume calculation approach is a hybrid methodology comprised of the Power Crust reconstruction and the Alpha Solid reconstruction. The Alpha Solid approach is to be used on small-scale point clouds, characterized with high curvatures relative to their sampling density, which challenge the Power Crust sampling assumptions.

scholarly journals Detonation effects of shallow buried explosive in sandy soil on target plate acceleration in a small-scale blast test

2018 ◽  
Vol 192 ◽  
pp. 02028
Author(s):  
Hassan Zulkifli Abu ◽  
Ibrahim Aniza ◽  
Mohamad Nor Norazman
Keyword(s):  
Sandy Soil ◽  
High Speed ◽  
Early Stage ◽  
Time History ◽  
Video Camera ◽  
Small Scale ◽  
Target Plate ◽  
Air Blast ◽  
High Speed Video Camera ◽  
The Impact

Small-scale blast tests were carried out to observe and measure the influence of sandy soil towards explosive blast intensity. The tests were to simulate blast impact imparted by anti-vehicular landmine to a lightweight armoured vehicle (LAV). Time of occurrence of the three phases of detonation phase in soil with respect to upward translation time of the test apparatus were recorded using high-speed video camera. At the same time the target plate acceleration was measured using shock accelerometer. It was observed that target plate deformation took place at early stage of the detonation phase before the apparatus moved vertically upwards. Previous data of acceleration-time history and velocity-time history from air blast detonation were compared. It was observed that effects of soil funnelling on blast wave together with the impact from soil ejecta may have contributed to higher blast intensity that characterized detonation in soil, where detonation in soil demonstrated higher plate velocity compared to what occurred in air blast detonation.

scholarly journals Bio-Inspired Covert Active Sonar Strategy

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2436 ◽  
Author(s):  
Jiajia Jiang ◽  
Xianquan Wang ◽  
Fajie Duan ◽  
Chunyue Li ◽  
Xiao Fu ◽  
...  
Keyword(s):  
Marine Mammals ◽  
Estimation Method ◽  
Sperm Whale ◽  
Waveform Design ◽  
Velocity Estimation ◽  
Estimation Methods ◽  
Range Resolution ◽  
Active Sonar ◽  
Ocean Noise ◽  
Underwater Target

The covertness of the active sonar is a very important issue and the sonar signal waveform design problem was studied to improve covertness of the system. Many marine mammals produce call pulses for communication and echolocation, and existing interception systems normally classify these biological signals as ocean noise and filter them out. Based on this, a bio-inspired covert active sonar strategy was proposed. The true, rather than man-made sperm whale, call pulses were used to serve as sonar waveforms so as to ensure the camouflage ability of sonar waveforms. A range and velocity measurement combination (RVMC) was designed by using two true sperm whale call pulses which had excellent range resolution (RR) and large Doppler tolerance (DT). The range and velocity estimation methods were developed based on the RVMC. In the sonar receiver, the correlation technology was used to confirm the start and end time of sonar signals and their echoes, and then based on the developed range and velocity estimation method, the range and velocity of the underwater target were obtained. Then, the RVMC was embedded into the true sperm whale call-train to improve the camouflage ability of the sonar signal-train. Finally, experiment results were provided to verify the performance of the proposed method.

scholarly journals Assessment of Stem Volume on Plots Using Terrestrial Laser Scanner: A Precision Forestry Application

Sensors ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 301
Author(s):  
Dimitrios Panagiotidis ◽  
Azadeh Abdollahnejad ◽  
Martin Slavík
Keyword(s):  
Norway Spruce ◽  
Laser Scanner ◽  
Estimation Methods ◽  
Coefficient Of Determination ◽  
Stem Volume ◽  
Small Scale ◽  
Terrestrial Laser Scanner ◽  
Precision Forestry ◽  
Total Tree ◽  
European Oak

Timber volume is an important asset, not only as an ecological component, but also as a key source of present and future revenues, which requires precise estimates. We used the Trimble TX8 survey-grade terrestrial laser scanner (TLS) to create a detailed 3D point cloud for extracting total tree height and diameter at breast height (1.3 m; DBH). We compared two different methods to accurately estimate total tree heights: the first method was based on a modified version of the local maxima algorithm for treetop detection, “HTTD”, and for the second method we used the centers of stem cross-sections at stump height (30 cm), “HTSP”. DBH was estimated by a computationally robust algebraic circle-fitting algorithm through hierarchical cluster analysis (HCA). This study aimed to assess the accuracy of these descriptors for evaluating total stem volume by comparing the results with the reference tree measurements. The difference between the estimated total stem volume from HTTD and measured stems was 2.732 m3 for European oak and 2.971 m3 for Norway spruce; differences between the estimated volume from HTSP and measured stems was 1.228 m3 and 2.006 m3 for European oak and Norway spruce, respectively. The coefficient of determination indicated a strong relationship between the measured and estimated total stem volumes from both height estimation methods with an R2 = 0.89 for HTTD and R2 = 0.87 for HTSP for European oak, and R2 = 0.98 for both HTTD and HTSP for Norway spruce. Our study has demonstrated the feasibility of finer-resolution remote sensing data for semi-automatic stem volumetric modeling of small-scale studies with high accuracy as a potential advancement in precision forestry.

scholarly journals Fixed Echo Rejection in Sodar Using Noncoherent Matched Filter Detection and Gaussian Mixture Model–Based Postprocessing

2019 ◽  
Vol 36 (1) ◽  
pp. 3-16
Author(s):  
Paul Kendrick ◽  
Sabine von Hünerbein
Keyword(s):  
Radial Velocity ◽  
Matched Filter ◽  
Gaussian Mixture ◽  
Urban Environments ◽  
Velocity Estimation ◽  
Estimation Methods ◽  
Chirp Pulse ◽  
Signal Processing Algorithm ◽  
Doppler Sodar ◽  
Wind Profiles

AbstractDoppler sodar is a technology used for acoustic-based remote sensing of the lower planetary boundary layer. Sodars are often used to measure wind profiles; however, they suffer from problems caused by noise (both acoustic and electrical) and echoes from fixed objects, which can bias radial velocity estimates. An experimental bistatic sodar was developed with 64 independent channels. The device enables flexible beamforming; beams can be tilted at the same angle irrelevant of frequency, a limitation in most commercial devices. This paper presents an alternative sodar signal-processing algorithm for wind profiling using a multifrequency stepped-chirp pulse. A noncoherent matched filter was used to analyze returned signals. The noncoherent matched filter combines radial velocity estimates from multiple frequencies into a single optimization. To identify and separate sources of backscatter, noise, and fixed echoes, a stochastic pattern-recognition technique, Gaussian mixture modeling, was used to postprocess the noncoherent matched filter data. This method allowed the identification and separation of different stochastic processes. After identification, noise and fixed echo components were removed and a clean wind profile was produced. This technique was compared with traditional spectrum-based radial velocity estimation methods, and an improvement in the rejection of fixed echo components was demonstrated; this is one of the major limitations of sodar performance when located in complex terrain and urban environments.

scholarly journals District level child nutrition status in Bangladesh: An application of small area estimation method

2019 ◽  
Vol 53 (1) ◽  
pp. 45-61
Author(s):  
Mossamet Kamrun Nesa
Keyword(s):  
Small Area ◽  
Child Nutrition ◽  
Small Area Estimation ◽  
Estimation Method ◽  
Nutrition Status ◽  
Estimation Methods ◽  
Small Scale ◽  
Demographic Health Survey ◽  
Area Estimation ◽  
National Surveys

National level indicators of child undernutrition often hide the real scenario across a country. In order to construct a child nutrition map, accurate estimates of undernutrition are required at very small spatial scales, typically the administrative units of a country or a region within a country. Although comprehensive data on child nutrition are collected in national surveys, the small scale estimates cannot be calculated using the standard estimation methods employed in national surveys, since such methods are designed to produce national or regional level estimates, and assume large samples. Small area estimation method has been widely used to find such micro-level estimates. Due to lack of unit level data, area level small area estimation methods (e.g., Fay-Herriot method) are widely used to calculate small-scale estimates. In Bangladesh, a few works have been done to estimate district level child nutrition status. The Bangladesh Demographic Health Survey covers all districts but district wise sample sizes are very small to get consistent estimates. In this paper, Fay-Herriot Model has been developed to calculate district wise estimates with efficient mean squared error. The Bangladesh Demographic Health Survey 2011 and Population Census 2011 are utilized for this study.

Supporting school leavers in areas of deprivation into initial positive leaver destinations

2013 ◽  
Vol 16 (1) ◽  
pp. 67-83 ◽  
Author(s):  
Stephen McKinney ◽  
Stuart Hall ◽  
Kevin Lowden ◽  
Michele McClung ◽  
Lauren Cameron
Keyword(s):  
Young People ◽  
Distributed Leadership ◽  
Early Stage ◽  
Child Poverty ◽  
Small Scale ◽  
School Leaver ◽  
The United Kingdom ◽  
The City ◽  
Detrimental Impact

The contemporary attempts to tackle poverty and child poverty in the United Kingdom have been seriously hindered by the effects of the economic crisis (Hirsch, 2008a; Mooney, 2011). The prevailing discourses of the recession and intergenerational poverty can lead to a view that the effects of child poverty and the consequent detrimental impact on school education and future prospects for some young people are intractable (Sinclair & McKendrick, 2009). There can be insufficient emphasis on the successful attempts, however fragile, to intervene in the cycle of deprivation. This article reports on research conducted in two contrasting groups of secondary schools in the city of Glasgow, located in areas of deprivation, as they work to secure initial positive school leaver destinations for young people. This small-scale case study highlights the importance of a strong leadership vision committed to initial positive school leaver destinations, but complemented by distributed leadership and support from external partners to enable sustained successes. It also highlights the importance of individual attention to all young people to support and motivate them and the effectiveness of intervention at an early stage.

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