scholarly journals Performance Analysis of Energy Harvesting UAV Selection

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Khuong Ho-Van ◽  
Thiem Do-Dac
Keyword(s):  
Physical Layer Security ◽  
Intercept Probability ◽  
Multiple Uavs ◽  
Radio Frequency Signals ◽  
Aerial Vehicle ◽  
Security And Reliability ◽  
Transmitted Signal ◽  
Operation Parameters ◽  
Reliability Performance ◽  
The Impact

In an UAV- (unmanned aerial vehicle-) aided relaying system, the transmitted signal is exposed to free space in two transmission hops which may be overheard by eavesdroppers. Accordingly, physical layer security should be exploited to improve information security. This paper analyzes both (security and reliability) performance aspects of such a system where only one UAV among multiple UAVs, all capable of harvesting energy from radio frequency signals, is adopted. Towards this end, the tight approximated and exact closed-form expressions of the outage probability at the legitimate destination and the intercept probability at the eavesdropper are first derived. Then, Monte-Carlo simulations are conducted to verify the derived expressions. Based on these expressions, the protected zone of the selected UAV is also proposed through an exhaustive search. Finally, various results are provided to illustrate the impact of key operation parameters on the system performance and the efficacy of the UAV selection.

scholarly journals Security-Reliability Tradeoff Analysis in Multisource Multirelay Cooperative Networks with Multiple Cochannel Interferers

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Weilong Hu ◽  
Jiangbo Si ◽  
Hongyan Li
Keyword(s):  
Fading Channels ◽  
Physical Layer Security ◽  
Communication Technologies ◽  
Cooperative Networks ◽  
Cooperative Relaying ◽  
Green Communication ◽  
Intercept Probability ◽  
Outage Probabilities ◽  
Reliability Performance ◽  
The Impact

Cooperative relaying communication is one of the green communication technologies since it shortens the communication distance and saves the transmit power. In this paper, the physical-layer security (PLS) of a multisource multirelay cooperative relaying communication network is investigated by considering the influence of cochannel interference from a security-reliability tradeoff (SRT) perspective. First, the SRT performance is characterized by the outage probability (OP) and the intercept probability (IP). In particular, the IP encountered at the eavesdropper is used to evaluate the security performance, while the reliability performance is analyzed in terms of the OP experienced at the destination. Then, under the impact of multiple cochannel interferers, the intercept probabilities and the outage probabilities of both the conventional direct transmission (DT) strategy and relay selection (RS) strategy are derived in closed-form expressions over Rayleigh fading channels, respectively. Simulation results are provided to validate the theoretical analysis. It is shown that when the OP (reliability) requirement is relaxed, the IP (security) performance improves and vice versa. It confirms that there is an SRT existing between the OP and the IP. Meanwhile, a better SRT performance can be achieved by increasing the number of sources, relays, and cochannel interferers. In addition, it is also shown that the RS strategy generally outperforms the conventional DT strategy in terms of the product of the IP and the OP.

scholarly journals PHYSICAL LAYER SECURITY OF WIRELESS SENSOR NETWORK BASED ON OPPORTUNISTIC SCHEDULING

2020 ◽  
Vol 19 (1) ◽  
pp. 001
Author(s):  
Ivica Marjanović ◽  
Dejan Milić ◽  
Jelena Anastasov ◽  
Aleksandra Cvetković
Keyword(s):  
Wireless Sensor Network ◽  
Sensor Network ◽  
Physical Layer Security ◽  
Security Analysis ◽  
Physical Layer ◽  
Wireless Sensor ◽  
Opportunistic Scheduling ◽  
Wiretap Channels ◽  
Intercept Probability ◽  
The Impact

In this paper, a physical layer security analysis of wireless sensor network in the presence of an attacker, employing opportunistic scheduling approach, is presented. The intended as well as unintended transmission paths experience the Weibull fading. A novel analytical expression for the intercept probability is derived. In order to emphasize the advantages of the opportunistic scheduling approach, a comparative analysis with round-robin and optimal scheduling schemes is also given. The impact of a number of active sensors and the impact of fading channel conditions over main and wiretap channels on the intercept probabilities is obtained. The accuracy of theoretical results is confirmed by independent Monte Carlo simulation results.

Energy absorbed ability and damage analysis for honeycomb sandwich material of bio-inspired micro aerial vehicle under low velocity impact

2020 ◽  
pp. 095440622097542
Author(s):  
Jianxun Du ◽  
Peng Hao ◽  
Mabao Liu ◽  
Rui Xue ◽  
Lin’an Li
Keyword(s):  
Honeycomb Structure ◽  
Low Velocity Impact ◽  
Parameter Study ◽  
Low Velocity ◽  
Micro Aerial Vehicle ◽  
Thin Walled Structures ◽  
Wide Range ◽  
Aerial Vehicle ◽  
Thin Walled ◽  
The Impact

Because of the advantages of light weight, small size, and good maneuverability, the bio-inspired micro aerial vehicle has a wide range of application prospects and development potential in military and civil areas, and has become one of the research hotspots in the future aviation field. The beetle’s elytra possess high strength and provide the protection of the abdomen while being functional to guarantee its flight performance. In this study, the internal microstructure of beetle’s elytra was observed by scanning electron microscope (SEM), and a variety of bionic thin-walled structures were proposed and modelled. The energy absorption characteristics and protective performance of different configurations of thin-walled structures with hollow columns under impact loading was analyzed by finite element method. The parameter study was carried out to show the influence of the velocity of impactor, the impact angle of the impactor and the wall thickness of honeycomb structure. This study provides an important inspiration for the design of the protective structure of the micro aerial vehicle.

A Novel Design of Landing Gear Oleo Strut Damper Using MR Fluid for Aircraft and UAV’s

2012 ◽  
Vol 225 ◽  
pp. 275-280
Author(s):  
Chandra B. Asthana ◽  
Rama B. Bhat
Keyword(s):  
Shock Absorber ◽  
Fluid Viscosity ◽  
Simulation Approach ◽  
Body Frame ◽  
Mr Fluid ◽  
Orifice Area ◽  
Aerial Vehicle ◽  
Impact Kinetic Energy ◽  
The Impact ◽  
Novel Design

Most landing gears used in aircraft employ very efficient oleo-pneumatic dampers to absorb and dissipate the impact kinetic energy of the aircraft body frame. A single-acting shock absorber is most commonly used in the oleo strut that has a metering pin extending through the orifice, which can vary the orifice area upon compression and extension of the strut. This variation is adjusted by shaping the metering pin so that the strut load is fairly constant under dynamic loading. In this paper, it is proposed to further change the damping coefficient as a function of time in order to achieve a semi-active control of the aircraft vibrations during landing by using Magnetorheological (MR) fluid in the Oleo. With the metering pin designed for a nominal flight condition, further variation in the fluid viscosity would help achieve the optimal performance in off-nominal flight conditions. A simulation approach is employed to show the effect of different profiles for viscosity variation in the MR fluid. The utility of such a damper can be very well exploited to include different criteria such as the landing distance after touchdown. This type of system can be used also in Unmanned Aerial Vehicle (UAV) application where the focus of design may be to accomplish the task without the consideration of passenger comfort.

Impact of N-Shaped Wing Morphing on Solar-Powered Aircraft

2020 ◽  
pp. 1-12
Author(s):  
Mostafa E. El-Salamony ◽  
Mohamed A. Aziz
Keyword(s):  
Solar Energy ◽  
Lift Coefficient ◽  
Morphing Wing ◽  
Aerial Vehicles ◽  
Aircraft Performance ◽  
Aerial Vehicle ◽  
Solar Powered ◽  
Two Parameters ◽  
Wing Morphing ◽  
The Impact

Generally, unmanned aerial vehicles and micro aerial vehicles depend on batteries or conventional fuel as a source of energy. These sources of energy have limited flight time, relatively high cost, and also a certain level of pollutants. Solar energy applied to aerial vehicles is an excellent alternative way to overcome other sources of energy’s disadvantage. This study aimed to design a solar-powered aerial vehicle to achieve continuous flight on Earth. The efficiency of the solar system is related to the absorbed sun rays. The concept of an anti-symmetric N-shaped morphing wing is a good idea to increase the collected solar energy during the daily sun path. But this comes with the penalty of side forces and moments due to the anti-symmetry of the wing. This paper introduces a study for two parameters that strongly affect the aerodynamics of the N-shaped morphing wing; the dihedral part angle and the dihedral part length. The impact of the dihedral angle decreases the lift coefficient and increases the drag coefficient. The impact of the morphing wing on the aircraft performance is also considered.

scholarly journals Automated Bale Mapping Using Machine Learning and Photogrammetry

2021 ◽  
Vol 13 (22) ◽  
pp. 4675
Author(s):  
William Yamada ◽  
Wei Zhao ◽  
Matthew Digman
Keyword(s):  
Lower Cost ◽  
Mean Squared Error ◽  
Spatial Clustering ◽  
Mean Average Precision ◽  
Average Precision ◽  
Data Set ◽  
Map Projection ◽  
Squared Error ◽  
Aerial Vehicle ◽  
The Impact

An automatic method of obtaining geographic coordinates of bales using monovision un-crewed aerial vehicle imagery was developed utilizing a data set of 300 images with a 20-megapixel resolution containing a total of 783 labeled bales of corn stover and soybean stubble. The relative performance of image processing with Otsu’s segmentation, you only look once version three (YOLOv3), and region-based convolutional neural networks was assessed. As a result, the best option in terms of accuracy and speed was determined to be YOLOv3, with 80% precision, 99% recall, 89% F1 score, 97% mean average precision, and a 0.38 s inference time. Next, the impact of using lower-cost cameras was evaluated by reducing image quality to one megapixel. The lower-resolution images resulted in decreased performance, with 79% precision, 97% recall, 88% F1 score, 96% mean average precision, and 0.40 s inference time. Finally, the output of the YOLOv3 trained model, density-based spatial clustering, photogrammetry, and map projection were utilized to predict the geocoordinates of the bales with a root mean squared error of 2.41 m.

scholarly journals Dynamic Stability and Control of a Manipulating Unmanned Aerial Vehicle

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Yunping Liu ◽  
Xijie Huang ◽  
Yonghong Zhang ◽  
Yukang Zhou
Keyword(s):  
Stability Analysis ◽  
Lyapunov Exponent ◽  
Dynamic Stability ◽  
Unmanned Aerial Vehicle ◽  
Impedance Control ◽  
System Stability ◽  
Constructive Method ◽  
Aerial Vehicle ◽  
And Control ◽  
The Impact

This paper focuses on the dynamic stability analysis of a manipulator mounted on a quadrotor unmanned aerial vehicle, namely, a manipulating unmanned aerial vehicle (MUAV). Manipulator movements and environments interaction will extremely affect the dynamic stability of the MUAV system. So the dynamic stability analysis of the MUAV system is of paramount importance for safety and satisfactory performance. However, the applications of Lyapunov’s stability theory to the MUAV system have been extremely limited, due to the lack of a constructive method available for deriving a Lyapunov function. Thus, Lyapunov exponent method and impedance control are introduced, and the Lyapunov exponent method can establish the quantitative relationships between the manipulator movements and the dynamics stability, while impedance control can reduce the impact of environmental interaction on system stability. Numerical simulation results have demonstrated the effectiveness of the proposed method.

A numerical investigation of the impact of shield machine’s operation parameters on the settlements above twin stacked tunnels - A case study of Ho Chi Minh urban railway Line 1

2021 ◽  
Author(s):  
Anh Do Ngoc ◽  
Daniel Dias ◽  
Thang Trong Dang
Keyword(s):  
Three Dimensional ◽  
Support Pressure ◽  
Reference Case ◽  
Railway Line ◽  
Grouting Pressure ◽  
The Face ◽  
Operation Parameters ◽  
Surface Settlements ◽  
Shield Machine ◽  
The Impact

Three-dimensional finite difference calculations are proposed to investigate the influence of operation parameters of the shield machines during twin stacked tunnel excavation on the surface settlements. The numerical model is validated by experimental data obtained from Hochiminh’s metro line 1 project, used as a reference case in this study. The parametric study focuses on the influence of the face support pressure, the grouting pressure, and the shield’s length. The numerical results indicated that a decrease does not always follow an increase in surface settlements' face and grouting pressure. A shorter shield machine causes smaller surface settlements to develop over single lower and twin stacked tunnels.

Evaluation of Polymer Core Solderballs for Wafer Level Reliability Improvements

2014 ◽  
Vol 2014 (DPC) ◽  
pp. 000545-000566
Author(s):  
John Hunt ◽  
Adren Hsieh ◽  
Eddie Tsai ◽  
Chienfan Chen ◽  
Tsaiying Wang
Keyword(s):  
Temperature Cycling ◽  
Wafer Level ◽  
Development Activity ◽  
Wafer Level Packaging ◽  
First Case ◽  
Mask Design ◽  
To Come ◽  
And Performance ◽  
Reliability Performance ◽  
The Impact

Nearly half a century ago the first die bumping was developed by IBM that would later enable what we call Wafer Level Packaging. It took nearly 40 years for Wafer Level Chip Scale Packaging (WLCSP), with all of the “packaging” done while still in wafer form to come into volume production. It began with very small packages having solderball counts of 2–6 I/Os. Over the years, the I/O count has grown, but much of the industry perception has remained that WLCSPs are limited to low I/O count, low power applications. But within the last few years, there have been growing demands for WLCSP packages to expand into applications with higher levels of complexity. With the ever increasing density and performance requirements for components in mobile electronic systems, the need has developed for an expansion of applicability for Wafer Level Package (WLP) technology. Wafer Level packaging has demonstrated a higher level of component density and functionality than has been traditionally available using standard packaging. This has led to the development of WLCSPs with larger die and increasing solderball connectivity counts. Development activity has been ongoing for improved materials and structures to achieve the required reliability performance for these larger die. For this study, we have evaluated several different metallic structures used for polymer core solderballs with two different WLCSP structures. The WLCSP structures which were evaluated included a standard 4-mask design with redistribution layer (RDL), using a Polymer 1, Metal RDL, Polymer2, and Under Bump Metallization (UBM); as well as a 3-mask design with RDL, using a Polymer 1, Metal RDL, and Polymer 2. In the first case, the solderballs are bonded to the UBM, while in the second case the balls are bonded to the RDL, using the Polymer 2 layer as the solder wettable defining layer. All of the combinations are tested using the standard JEDEC Temperature Cycling on Board (TCOB) and Drop Test (DT) methodologies. The two different metallurgies of the polymer core solderballs appear to react differently to the two different WLCSP structures. This suggests that the polymer core solderball compositions may perform best when optimized for the specific WLCSP structures that are manufactured. We will review the results of the impact of the different polymer core metallurgies on the TCOB and DT reliability performance of the WLCSPs, showing the interactions of these materials with the two WLCSP structures.

Impact of E-Services Quality on E-Loyalty in Paltel E-Satisfaction as a Mediating Variable

2020 ◽  
Vol 12 (2) ◽  
pp. 81-101
Author(s):  
Maan Ali Alkhateeb
Keyword(s):  
Service Quality ◽  
Quantitative Research ◽  
Services Quality ◽  
Customer Retention ◽  
Research Approach ◽  
Content Structure ◽  
Structure Interaction ◽  
Independent Variable ◽  
Security And Reliability ◽  
The Impact

E-loyalty has received great interest from researchers as a key element for customer retention and the growth of firms as well as gaining new customers. This study aims to investigate the impact of the electronic website services quality on e-loyalty in the companies listed within Paltel using electronic satisfaction as a mediating variable. Seven dimensions of e-service quality are examined including content, structure, interaction, presentation, responsiveness, e-security, and reliability. The quantitative research approach is conducted on the returned 393 valid surveys. The findings revealed and emphasized the role played by e-satisfaction as a mediating variable between the independent variable's dimensions and the independent variable.

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