scholarly journals Handling Qualities Analysis of an Unmanned Aircraft Vehicle for Agricultural Spraying

2020 ◽  
pp. 38-51
Author(s):  
Artur Gustavo Slongo ◽  
Deniel Desconzi Moraes ◽  
Lorenzzo Quevedo Mantovani ◽  
Mateus Schmitz Venturini
Keyword(s):  
Pest Control ◽  
Precision Agriculture ◽  
Unmanned Aircraft ◽  
Handling Qualities ◽  
Control Chemical ◽  
Handling Quality ◽  
The Impact ◽  
Aircraft Data

The use of unmanned aircraft vehicles (UAVs) for the most diverse aeronautic missions is a reality. Then, with the rise of precision agriculture (PA), the viability of the incorporation of this technology in the countryside on both big and small proprieties is under study. This work aims to analyze the handling qualities of an UAV with a mission of pest control chemical spraying. With this objective, aircraft data was used to analyze the eigenvalues of the aircraft modes. Then, the impact of mass and inertia variation during its mission was studied. Also, the longitudinal and latero-directional dynamics were evaluated based on the Cooper–Harper scale. The results found indicate that all aircraft modes are stable for both full hopper and empty hopper conditions. Moreover, the determined handling quality grades of the UAV in the Cooper–Harper scale indicate the need for some correction applied by the pilot during flight.

scholarly journals Composite Impact of Global Hawk Unmanned Aircraft Dropwindsondes on Tropical Cyclone Analyses and Forecasts

2018 ◽  
Vol 146 (7) ◽  
pp. 2297-2314 ◽  
Author(s):  
Hui Christophersen ◽  
Altug Aksoy ◽  
Jason Dunion ◽  
Sim Aberson
Keyword(s):  
Tropical Cyclone ◽  
Positive Impact ◽  
Unmanned Aircraft ◽  
Wind Pressure ◽  
Intensity Change ◽  
Lead Times ◽  
Nonsteady State ◽  
The Impact ◽  
Aircraft Data ◽  
Global Hawk

Abstract The impacts of Global Hawk (GH) dropwindsondes on tropical cyclone (TC) analyses and forecasts are examined over a composite sample of missions flown during the NASA Hurricane and Severe Storm Sentinel (HS3) and the NOAA Sensing Hazards with Operational Unmanned Technology (SHOUT) field campaigns. An ensemble Kalman filter is employed to assimilate the dropwindsonde observations at the vortex scale. With the assimilation of GH dropwindsondes, TCs generally exhibit fewer position and intensity errors, a better wind–pressure relationship, and improved representation of integrated kinetic energy in the analyses. The resulting track and intensity forecasts with all the cases generally show a positive impact when GH dropwindsondes are assimilated. The impact of GH dropwindsondes is further explored with cases stratified by intensity change and presence of crewed aircraft data. GH dropwindsondes demonstrate a larger impact for nonsteady-state TCs [non-SS; 24-h intensity change larger than 20 kt (~10 m s−1)] than for steady-state (SS) TCs. The relative skill from assimilating GH dropwindsondes ranges between 25% and 35% for either the position or intensity improvement in the final analyses overall, but only ~5%–10% for SS cases alone. The resulting forecasts for non-SS cases show higher skill for both track and intensity than SS cases. In addition, the GH dropwindsonde impact on TC forecasts varies in the presence of crewed aircraft data. An increased intensity improvement at long lead times is seen when crewed aircraft data are absent. This demonstrates the importance of strategically designing flight patterns to exploit the sampling strengths of the GH and crewed aircraft in order to maximize data impacts on TC prediction.

The Impact of Employee Empathy on Brand Trust in Organizational Complaint Response Emails: A Closer Look at Linguistic Realization

2021 ◽  
pp. 232948842110323
Author(s):  
Rebecca Van Herck ◽  
Sofie Decock ◽  
Bernard De Clerck ◽  
Liselot Hudders
Keyword(s):  
Positive Impact ◽  
Brand Trust ◽  
Mediating Effects ◽  
Customer Complaints ◽  
Moderation Effects ◽  
Complaint Handling ◽  
Negative Effect ◽  
Handling Quality ◽  
The Impact

This study investigates the effect of linguistic realizations of employee empathy (LREE) on brand trust in email responses to customer complaints. We explore possible mediating effects of perceived empathy and perceived complaint handling quality and we look into moderation effects of compensation (Study 1) or customer’s acceptance of blame (Study 2). Our aim is to find out if LREE have a negative or positive impact on the customer in cases of partial refunds, either because LREE are being perceived as insincere or as genuine expressions of concern. The results of two experiments show that LREE positively influence brand trust through higher perceived empathy and perceived complaint handling quality. However, the expected negative effect is not found, as LREE are more effective in a low versus high compensation condition. The effectiveness itself is not influenced by the acceptance of blame when a partial refund is offered.

Impact of UAS with Low Size, Weight, and Power Sensors on Air Traffic Controllers’ Performance and Acceptability Ratings

2020 ◽  
Vol 64 (1) ◽  
pp. 154-158
Author(s):  
Kim-Phuong L. Vu ◽  
Jonathan VanLuven ◽  
Timothy Diep ◽  
Vernol Battiste ◽  
Summer Brandt ◽  
...  
Keyword(s):  
Air Traffic ◽  
Unmanned Aircraft ◽  
Unmanned Aircraft Systems ◽  
Subjective Ratings ◽  
Detection Range ◽  
Human In The Loop ◽  
Air Traffic Controllers ◽  
Low Altitude ◽  
Sector Performance ◽  
The Impact

A human-in-the-loop simulation was conducted to evaluate the impact of Unmanned Aircraft Systems (UAS) with low size, weight, and power (SWaP) sensors operating in a busy, low-altitude sector. Use of low SWaP sensors allow for UAS to perform detect-and-avoid (DAA) maneuvers against non-transponding traffic in the sector. Depending upon the detection range of the low SWaP sensor, the UAS pilot may or may not have time to coordinate with air traffic controllers (ATCos) prior to performing the DAA maneuver. ATCo’s sector performance and subjective ratings of acceptability were obtained in four conditions that varied in UAS-ATCo coordination (all or none) prior to the DAA maneuver and workload (higher or lower). For performance, ATCos committed more losses of separation in high than low workload conditions. They also had to make more flight plan changes to manage the UAS when the UAS pilot did not coordinate DAA maneuvers compared to when they did coordinate the maneuvers prior to execution. Although the ATCos found the DAA procedures used by the UAS in the study to be acceptable, most preferred the UAS pilot to coordinate their DAA maneuvers with ATCos prior to executing them.

Altitude Effects on the Performance of Small Radial Turbomachinery: Part I — Compressor Impellers

2016 ◽  
Author(s):  
Dries Verstraete ◽  
Kjersti Lunnan
Keyword(s):  
Reynolds Number ◽  
Performance Analysis ◽  
Rotational Speed ◽  
Pressure Ratio ◽  
Unmanned Aircraft ◽  
Good Match ◽  
One Dimensional ◽  
Design Changes ◽  
Current Article ◽  
The Impact

Small unmanned aircraft are currently limited to flight ceilings below 20,000 ft due to the lack of an appropriate propulsion system. One of the most critical technological hurdles for an increased flight ceiling of small platforms is the impact of reduced Reynolds number conditions at altitude on the performance of small radial turbomachinery. The current article investigates the influence of Reynolds number on the efficiency and pressure ratio of two small centrifugal compressor impellers using a one-dimensional meanline performance analysis code. The results show that the efficiency and pressure ratio of the 60 mm baseline compressor at the design rotational speed drops with 6–9% from sea-level to 70,000 ft. The impact on the smaller 20 mm compressor is slightly more pronounced and amounts to 6–10%. Off-design changes at low rotational speeds are significantly higher and can amount to up to 15%. Whereas existing correlations show a good match for the efficiency drop at the design rotational speed, they fail to predict efficiency changes with rotational speed. A modified version is therefore proposed.

scholarly journals Crop Diversification Affects Biological Pest Control

2013 ◽  
Vol 14 (3) ◽  
pp. 449 ◽  
Author(s):  
Dimitrije Marković
Keyword(s):  
Pest Control ◽  
Habitat Management ◽  
Crop Diversification ◽  
Agricultural Systems ◽  
Beneficial Arthropods ◽  
Habitat Manipulation ◽  
Biological Pest Control ◽  
Agricultural Ecosystems ◽  
The Impact

Crop monocultures encourage the multiplication and spread of pest insects on massive and uniform crop. Numerous studies have evaluated the impact of plant diversification on pests and beneficial arthropods population dynamics in agricultural ecosystems and provided some evidence that habitat manipulation techniques like intercropping can significantly influence pest control. This paper describes various potential options of habitat management and design that enhance ecological role of biodiversity in agroecosystems. The focus of this review is the application and mechanisms of biodiversity in agricultural systems to enhance pest management.

Development and Flight Validation of Proposed Unmanned Aerial System Handling Qualities Requirements

2021 ◽  
Author(s):  
Christina M. Ivler ◽  
Kevin Truong ◽  
Declan Kerwin ◽  
Joel Otomize ◽  
Danielle Parmer ◽  
...  
Keyword(s):  
Large Scale ◽  
Performance Standards ◽  
Unmanned Aircraft ◽  
Performance Standard ◽  
Great Promise ◽  
Unmanned Aerial Systems ◽  
Dynamic Scaling ◽  
Scoring Method ◽  
Handling Qualities ◽  
Aerial Systems

Unmanned aerial systems, commonly known as drones, present new opportunities to perform autonomous tasks. Handling qualities requirements for manned vertical lift aircraft have been well defined and documented. The need to define handling qualities requirements for vertical take-off and landing (VTOL) unmanned aerial systems (UAS) to meet mission demands is of paramount importance for all potential operators and procurement agencies. One way to relate handling qualities specifications of large-scale manned and subscale unmanned aircraft is through Froude dynamic scaling. Froude dynamic scaling based on hub-to-hub distance has shown great promise in relating the natural frequencies of scaled multicopters. There have been recent efforts to develop a VTOL-UAS handling qualities standard by scaling mission task elements and rating their performance through a Trajectory, Tracking, and Aggression (TTA) score. This paper proposes a new performance standard adapted from the TTA scoring method, along with a modified Cooper–Harper scale as a VTOL-UAS handling qualities framework that is consistent with the spirit of Aeronautical Design Standard 33 (ADS-33). These newly proposed performance standards were then validated through simulation and flight testing on a small hexacopter UAS, flown at the University of Portland. A key outcome of this work is the flight verification of a key dynamic response metric, the disturbance rejection bandwidth, and associated validation of Froude scaling for predicted handling qualities metrics.

Satellite Channels Based on IEEE 802.16 Standard

2019 ◽  
pp. 133-166
Keyword(s):  
Frequency Shift ◽  
Communication Channels ◽  
Ieee 802.16 ◽  
Original Model ◽  
Doppler Shifts ◽  
Time Diversity ◽  
Different Types ◽  
Satellite Channels ◽  
The Impact ◽  
Aircraft Data

This chapter considers the modeling of RPAS/Aircraft data transmission via channels based on IEEE 802.16 standard. RPAS communication channel with a fading was analyzed using original model. Dependencies of a SNR in ground receiver on a SNR in downlink for different types of RPAS amplifier nonlinearity were obtained. Signals constellations of received signals were compared for different Doppler shifts. The influence of the aircraft transmitter nonlinearity for different types of fading in the channel was studied using “80216dstbc Rayleigh,” “80216dstbc Rician,” “80216d Rayleigh,” and “80216d Rician” models. The possibility of the nonlinearity correction using pre-distortion was revealed. The impact of space-time diversity (MISO 2x1) for different types of fading in the channels was investigated. The effect of the Doppler's frequency shift on the operation of communication channels was analyzed.

Introduction to Agricultural Information Systems

2021 ◽  
pp. 1-12
Author(s):  
Narasimha Rao Vajjhala
Keyword(s):  
Information Systems ◽  
Precision Agriculture ◽  
Management Information Systems ◽  
Farm Management ◽  
Management Information ◽  
Adoption And Implementation ◽  
Key Issues ◽  
Current Context ◽  
The Impact ◽  
Efficiency And Productivity

This chapter provides an introduction to agricultural and farm management information systems. This chapter provides an overview of the components, subsystems, processes, and operations in agricultural information systems. This chapter also covers the impact of these systems in improving the efficiency, and productivity of farm output. This chapter introduces several technologies related to the use of information systems in agriculture, including agricultural information systems (AIS), farm management information systems (FMIS), e-agriculture, and precision agriculture. This chapter introduces state-of-the-art technologies used in agriculture in the current context apart from providing an introduction to the use and adoption rates of these information systems. This chapter concludes with a brief discussion on the issues facing the adoption and implementation of agricultural information systems and presents some of the key issues that decision makers need to take to improve the acceptance and use of these information systems.

scholarly journals Inherent Reflectance Variability of Vegetation

Agriculture ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 246 ◽  
Author(s):  
Baabak Mamaghani ◽  
M. Grady Saunders ◽  
Carl Salvaggio
Keyword(s):  
Remote Sensing ◽  
Precision Agriculture ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Remote Sensing Data ◽  
Time Of Day ◽  
Unmanned Aircraft ◽  
P Value ◽  
Ground Sample ◽  
Significant Difference

With the inception of small unmanned aircraft systems (sUAS), remotely sensed images have been captured much closer to the ground, which has meant better resolution and smaller ground sample distances (GSDs). This has provided the precision agriculture community with the ability to analyze individual plants, and in certain cases, individual leaves on those plants. This has also allowed for a dramatic increase in data acquisition for agricultural analysis. Because satellite and manned aircraft remote sensing data collections had larger GSDs, self-shadowing was not seen as an issue for agricultural remote sensing. However, sUAS are able to image these shadows which can cause issues in data analysis. This paper investigates the inherent reflectance variability of vegetation by analyzing six Coneflower plants, as a surrogate for other cash crops, across different variables. These plants were measured under different forecasts (cloudy and sunny), at different times (08:00 a.m., 09:00 a.m., 10:00 a.m., 11:00 a.m. and 12:00 p.m.), and at different GSDs (2, 4 and 8 cm) using a field portable spectroradiometer (ASD Field Spec). In addition, a leafclip spectrometer was utilized to measure individual leaves on each plant in a controlled lab environment. These spectra were analyzed to determine if there was any significant difference in the health of the various plants measured. Finally, a MicaSense RedEdge-3 multispectral camera was utilized to capture images of the plants every hour to analyze the variability produced by a sensor designed for agricultural remote sensing. The RedEdge-3 was held stationary at 1.5 m above the plants while collecting all images, which produced a GSD of 0.1 cm/pixel. To produce 2, 4, and 8 cm GSD, the MicaSense RedEdge-3 would need to be at an altitude of 30.5 m, 61 m and 122 m respectively. This study did not take background effects into consideration for either the ASD or MicaSense. Results showed that GSD produced a statistically significant difference (p < 0.001) in Normalized Difference Vegetation Index (NDVI, a commonly used metric to determine vegetation health), R 2 values demonstrated a low correlation between time of day and NDVI, and a one-way ANOVA test showed no statistically significant difference in the NDVI computed from the leafclip probe (p-value of 0.018). Ultimately, it was determined that the best condition for measuring vegetation reflectance was on cloudy days near noon. Sunny days produced self-shadowing on the plants which increased the variability of the measured reflectance values (higher standard deviations in all five RedEdge-3 channels), and the shadowing of the plants decreased as time approached noon. This high reflectance variability in the coneflower plants made it difficult to accurately measure the NDVI.

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