This work was partially supported by the European H2020 5GRANGE project (grant agreement 777137), and by the 5GCIty project (TEC2016-76795-C6-3-R) funded by the Spanish Ministry of Economy and Competitiveness. The work of Luis F. Gonzalez was partially supported by the European H2020 5GinFIRE project (grant agreement 732497).

<ol>
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F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=NFV+orchestration+on+intermittently+available+SUAV+platforms:+challenges+and+hurdles.">NFV orchestration on intermittently available SUAV platforms: challenges and hurdles.</a> 1th Mission-Oriented Wireless Sensor, UAV and Robot Networking (MISARN). , (2019).</li><li>Nogales, B., Sanchez-Aguero, V., Vidal, I., Valera, F., Garcia-Reinoso, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+NFV+system+to+support+configurable+and+automated+multi-UAV+service+deployments.">A NFV system to support configurable and automated multi-UAV service deployments.</a> Proceedings of the 4th ACM Workshop on Micro Aerial Vehicle Networks, Systems, and Applications. , 39-44 (2018).</li><li>Nogales, B., Sanchez-Aguero, V., Vidal, I., Valera, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adaptable+and+automated+small+UAV+deployments+via+virtualization.">Adaptable and automated small UAV deployments via virtualization.</a> Sensors. 18 (12), 4116 (2018).</li><li>Hoban, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+ETSI+OSM+Community+White+Paper,+OSM+Release+FOUR:+A+Technical+Overview.">An ETSI OSM Community White Paper, OSM Release FOUR: A Technical Overview.</a> European Telecommunications Standards Institute. (ETSI). , (2018).</li><li>Quick start installation and use guide. Open Source MANO Release FOUR Available from: <a target="_blank" href="https://osm.etsi.org/wikipub/index.php/OSM_Release_FOUR">https://osm.etsi.org/wikipub/index.php/OSM_Release_FOUR</a> (2019)</li><li>Open Source Software for Creating Private and Public Clouds. OpenStack Available from: <a target="_blank" href="https://docs.openstack.org/ocata">https://docs.openstack.org/ocata</a> (2019)</li><li>OpenStack Installation Tutorial for Ubuntu. OpenStack Available from: <a target="_blank" href="https://docs.openstack.org/ocata/install-guide-ubuntu/">https://docs.openstack.org/ocata/install-guide-ubuntu/</a> (2019)</li><li>Linphone. An Open Source VoIP SIP Softphone for voice/video calls and instant messaging. Linphone Available from: <a target="_blank" href="https://www.linphone.org">https://www.linphone.org</a> (2019)</li><li>An Open Source Project to easily build and deploy secure video-conferencing solutions. 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The authors have nothing to disclose.

One of the most important aspects of this experiment is the use of virtualization technologies and NFV standards with UAV platforms. NFV presents a new paradigm aiming to decouple the hardware dependency of the network functionalities, thus enabling the provision of these functionalities through softwarization. Accordingly, the experiment does not depend on the use of the hardware equipment specified in the protocol. Alternatively, different models of single board computers can be selected, as long as they are in line with the dimensions and the transport capacity of the UAVs and they support Linux containers.
Notwithstanding this flexibility in terms of hardware selection, all the content provided for the reproducibility of the experiment is oriented towards the use of open source technologies. In this context, the configuration aspects and the software tools are conditioned to the use of Linux as the operating system.
On the other hand, the experiment considers the interoperation of two different computational platforms (i.e., the UAV cloud platform and the core cloud platform) to provide a moderately complex network service. However, this is not strictly needed, and the protocol could be followed to support scenarios in which only the UAV cloud platform is involved.
In addition, the solution presented could potentially be used in other environments, where resource-constrained hardware platforms might be available with the needed capacity to execute virtualization containers (e.g., the Internet of Things, or IoT, environments). In any case, the applicability of this solution to different environments and its potential adaptations will require a careful study in a case-by-case basis.
Finally, it should be noted that the results presented have been obtained in a laboratory environment and with the UAV devices grounded or following a limited and well-defined flight plan. Other scenarios involving outdoor deployments may introduce conditions affecting the stability of the flight of the UAVs, and hence the performance of the IP telephony service.

One of the most coveted goals within the new era of the mobile communications (most commonly known as the 5th mobile generation or 5G) is to be able to provide robust information technology services in situations where the primary telecommunications infrastructure may not be available (e.g., due to an emergency). In this context, the UAVs are receiving increasing attention from the research community due to their inherent versatility. There are numerous works that use these devices as a cornerstone for the provision of a large variety of services. For instance, the literature has analyzed the capacity of these devices to build an aerial communication infrastructure to accommodate multimedia services1,2,3. Furthermore, prior research has shown how the cooperation among several UAVs can extend the functionality of different communication services such as surveillance4, collaborative search and rescue5,6,7,8, or agribusiness9.
On the other hand, the NFV technology has acquired great significance within the telecom operators as one of the 5G key enablers. NFV represents a paradigmatic change regarding the telecommunications infrastructure by alleviating the current dependency of network appliances on specialized hardware through the softwarization of the network functionalities. This enables a flexible and agile deployment of new types of communication services. To this purpose, the European Telecommunications Standards Institute (ETSI) formed a specification group to define the NFV architectural framework10. Additionally, the ETSI currently hosts the Open Source Mano (OSM) group11, which is in charge of developing an NFV Management and Orchestration (MANO) software stack aligned with the definition of the ETSI NFV architectural framework.
Given all the aforementioned considerations, the synergic convergence between UAVs and NFV technologies is currently being studied in the development of novel network applications and services. This is illustrated by several research works in the literature that point out the advantages of these types of systems14,15,16, identify the challenges of this convergence and its missing aspects, highlight future research lines on this topic17, and present pioneer solutions based on open source technologies.
In particular, the integration of NFV technologies into the UAV arena enables the rapid and flexible deployment of network services and applications over delimited geographic areas (e.g., an IP telephony service). Following this approach, a number of UAVs can be deployed over a specific location, transporting compute platforms as payload (e.g., small-size single board computers). These compute platforms would provide a programmable network infrastructure (i.e., an NFV infrastructure) over the deployment area, supporting the instantiation of network services and applications under the control of a MANO platform.
Notwithstanding the benefits, the realization of this view presents a set of fundamental challenges that needs to be carefully addressed, such as the appropriate integration of these compute platforms as an NFV infrastructure, using an existing NFV software stack, so that an NFV orchestration service can deploy virtual functions on the UAVs; the constraints in terms of the computational resources provided by the compute platforms, as the UAVs transporting them may typically present limitations in terms of size, weight, and computing capacity of payload equipment; the proper placement of the virtual functions onto UAVs (i.e., selecting the best UAV candidate to deploy a particular virtual function); the maintenance of the control communications with the UAVs in order to manage the lifecycle of the VNFs in spite of the potentially intermittent availability of network communications with them (e.g., caused by mobility and battery constraints); the limited operation time of the UAVs due to their battery consumption; and the migration of the virtual functions when a UAV needs to be replaced due to its battery exhaustion. These benefits and challenges are detailed in previous work18,19 that includes the design of an NFV system capable of supporting the automated deployment of network functions and services on UAV platforms, as well as the validation of the practical feasibility of this design.
In this context, this paper focuses on describing a protocol to enable the automated deployment of moderately complex network services over a network of UAVs using the NFV standards and open source technologies. To illustrate the different steps of the protocol, a re-elaboration of an experiment presented in Nogales et al.19 is presented, consisting of the deployment of an IP telephony service. To aid the reproducibility of this work, real flight is considered as optional in the presented procedure, and performance results are obtained with the UAV devices on the ground. Interested readers should be able to replicate and validate the execution of the protocol, even in a controlled laboratory environment.
Figure 1 illustrates the network service designed for this procedure. This network service is built as a composition of specific softwarization units (categorized within the NFV paradigm as Virtual Network Functions, or VNFs) and provides the functionality of an IP telephony service to users in the vicinity of the UAVs. The VNF composing the service are defined as follows:
<ul>
	<li>Access Point VNF (AP-VNF): This VNF provides a Wi-Fi access point to end-user equipment (i.e., IP phones in this experiment).</li>
	<li>IP telephony server VNF (IP-telephony-server-VNF): It is responsible for managing the call signaling messages that are exchanged between IP phones to establish and terminate a voice call.</li>
	<li>Domain Name System VNF (DNS-VNF): This VNF provides a name resolution service, which is typically needed in IP telephony services.</li>
	<li>Access router VNF (AR-VNF): provides network routing functionalities, supporting the exchange of traffic (i.e., call signaling in this experiment) between the IP phones and the telecommunication operator domain.</li>
	<li>Core router VNF (CR-VNF): provides network routing functionalities in the telecommunication operator domain, offering access to operator-specific services (i.e., the IP telephony server) and external data networks.</li>
</ul>
Moreover, Figure 1 presents the physical devices used for the experiment, how they are interconnected, and the specific allocation of VNFs to devices.

<table><tbody><tr><td>AR. Drone 2.0 - Elite edition</td><td>Parrot</td><td></td><td>UAV used in the experiment to transport the RPis and thus, provide mobility to the compute units of the UAV cloud platform.</td></tr><tr><td>Bebop 2</td><td>Parrot</td><td></td><td>UAV used in the experiment to transport the RPis and thus, provide mobility to the compute units of the UAV cloud platform.</td></tr><tr><td>Commercial Intel Core Mini-ITX Computer</td><td>Logic Suppy</td><td></td><td>Computer server which hosts the OpenStack controller node (being executed as a VM) of the experiment&#039;s UAV cloud platform. In addition, another unit of this equipment (along with the RPis) conforms the computational resources of the UAV cloud platform.</td></tr><tr><td>Linux Containers (LXC)</td><td>Canonical Ltd.</td><td></td><td>(Software) Virtualization technology that enables the supply of the Virtual Network Functions detailed in the experiment. Source-code available online: https://linuxcontainers.org</td></tr><tr><td>Lithium Battery Pack Expansion Board. Model KY68C-UK</td><td>Kuman</td><td></td><td>Battery-power supply HAT (Hardware Attached on Top) for the computation units of the UAV cloud platform (i.e., the Raspberry Pis). In addition, this equipment encompasses the case used to attach the compute units (i.e., the Raspberry PIs or RPis) to the UAVs.</td></tr><tr><td>MacBook Pro</td><td>Apple</td><td></td><td>Commodity laptop utilized during the experiment to obtain and gather the results as described in the manuscript.</td></tr><tr><td>ns-3 Network Simulator</td><td>nsnam</td><td></td><td>(Software) A discrete-event simulator network simulator which provides the underlying communication substrate to the emulation station explained in the &quot;Protocol&quot; section (more specifically in the step &quot;2. Validate the functionality of the softwarization units via Emulation&quot;). Source-code available online: https://www.nsnam.org</td></tr><tr><td>Open Source MANO (OSM) - Release FOUR</td><td>ETSI OSM - Open source community</td><td></td><td>(Software) Management and Orchestration (MANO) software stack of the NFV system configured in the experiment. Source-code available online: https://osm.etsi.org/wikipub/index.php/OSM_Release_FOUR</td></tr><tr><td>OpenStack - Release Ocata</td><td>OpenStack - Open source community</td><td></td><td>(Software) Open source software used for setting up both the UAV cloud platform and the core cloud within the experiment. Source-code available online: https://docs.openstack.org/ocata/install-guide-ubuntu</td></tr><tr><td>Ping</td><td>Open source tool</td><td></td><td>(Software) An open source test tool, which verifies the connectivity between two devices connected through a communications network. In addition, this tool allows to assess the network performance since it calculates the Round Trip Time (i.e., the time taken to send and received a data packet from the network). Source-code available online: https://packages.debian.org/es/sid/iputils-ping</td></tr><tr><td>Power Edge R430</td><td>Dell</td><td></td><td>High-profile computer server which provides the computational capacity within the core cloud platform presented in the experiment.</td></tr><tr><td>Power Edge R630</td><td>Dell</td><td></td><td>Equipment used for hosting the virtual machine (VM) on charge of executing the MANO stack. In addition, the OpenStack controller node is also executed as a VM in this device. Note that the use of this device is not strictly needed. The operations carried out by this device could be done by a lower performance equipment due to the non-high resource specifications of the before mentioned VMs.</td></tr><tr><td>Prestige 2000W</td><td>ZyXEL</td><td></td><td>Voice over IP Wi-FI phone, compatible with the IEEE 802.11b wireless communications standard. This device is utilized to carry out the VoIP call through the network service hosted by platform described for the execution of the experiment.</td></tr><tr><td>Raspberry PI. Model 3b</td><td>Raspberry Pi Foundation</td><td></td><td>Selected model of Single Board Computer (SBC) used for providing the computational capacity to the experiment&#039;s UAV cloud platform.</td></tr><tr><td>SIPp</td><td>Open source tool</td><td></td><td>(Software) An open source test tool, which generates SIP protocol traffic. This tool allows to verify the proper support of the signalling traffic required in an IP telephony service such as the one deployed in the experiment. Source-code available online: http://sipp.sourceforge.net</td></tr><tr><td>Tcpdump</td><td>Open source tool</td><td></td><td>(Software) An open source tool that enables the capture and analysis of the network traffic. Source-code available online: https://www.tcpdump.org</td></tr><tr><td>Trafic</td><td>Open source tool</td><td></td><td>(Software) An open souce flow scheduler that is used for validating the capacity of the network service deployed to process data traffic generated during an IP telephony call. Source-code available online at: https://github.com/5GinFIRE/trafic</td></tr></tbody></table>

automated deployment of an internet protocol telephony service on unmanned aerial vehicles using network functions virtualization

The Network Function Virtualization (NFV) paradigm is one of the key enabling technologies in the development of the 5th generation of mobile networks. This technology aims to lessen the dependence on hardware in the provision of network functions and services by using virtualization techniques that allow the softwarization of those functionalities over an abstraction layer. In this context, there is increasing interest in exploring the potential of unmanned aerial vehicles (UAVs) to offer a flexible platform capable of enabling cost-effective NFV operations over delimited geographic areas.
To demonstrate the practical feasibility of utilizing NFV technologies in UAV platforms, a protocol is presented to set up a functional NFV environment based on open source technologies, in which a set of small UAVs supply the computational resources that support the deployment of moderately complex network services. Then, the protocol details the different steps needed to support the automated deployment of an internet protocol (IP) telephony service over a network of interconnected UAVs, leveraging the capacities of the configured NFV environment. Experimentation results demonstrate the proper operation of the service after its deployment. Although the protocol focuses on a specific type of network service (i.e., IP telephony), the described steps may serve as a general guide to deploy other type of network services. On the other hand, the protocol description considers concrete equipment and software to set up the NFV environment (e.g., specific single board computers and open source software). The utilization of other hardware and software platforms may be feasible, although the specific configuration aspect of the NFV environment and the service deployment may present variations with respect to those described in the protocol.

Based on the data obtained during the execution of the experiment, in which a real VoIP call is executed and following the steps indicated by the protocol to gather this information, Figure 2 depicts the cumulative distribution function of the end-to-end delay measured between two end-user equipment items (i.e., a commodity laptop and an IP telephone). This user equipment represents two devices that are interconnected through the AP VNFs of the deployed network service. More than 80% of the end-to-end delay measurements were below 60 ms, and none of them were higher than 150 ms, which guarantees appropriate delay metrics for the execution of a voice call.
Figure 3 illustrates the exchange of DNS and SIP signaling messages. These messages correspond to the registration of one of the users in the IP telephony server (i.e., the user whose IP phone is connected to the AP VNF where the &#34;tcpdump&#34; tool is running) and to the establishment of the voice call.
Finally, Figure 4 and Figure 5 show the data traffic captured during the call. In particular, the first one represents the constant stream of voice packets transmitted and received by one of the wireless phones during the call, whereas the latter illustrates the jitter in the forward direction with an average value lower than 1 ms.
The results that were obtained in the experiment for the delay figures (end-to-end delay and jitter) satisfy the recommendations specified by the International Telecommunication Union - Telecommunication Standardization Sector (ITU-T)35. Accordingly, the voice call progressed with no glitches and good sound quality. This experiment validated the practical feasibility of using NFV technologies and UAVs to deploy a functional IP telephony service.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/60425/60425fig01.jpg" /> 
Figure 1: Overview of the network service, depicting the VNFs, the entities in which they are executed, and the virtual networks needed for the provision of the IP telephony service. <a href="https://www.jove.com/files/ftp_upload/60425/60425fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/60425/60425fig02.jpg" /> 
Figure 2: End-to-end delay. Representation of the end-to-end delay offered to the end-user equipment connected to the AP VNFs. For this purpose, the cumulative distribution function of the end-to-end delay has been computed from the measured RTT samples obtained with the &#34;ping&#34; command line tool. <a href="https://www.jove.com/files/ftp_upload/60425/60425fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/60425/60425fig03.jpg" /> 
Figure 3: User registration and call signaling messages. Illustration of the signaling traffic (DNS and SIP) exchanged to register a user in the IP telephony server and to create and terminate the multimedia session that supports the execution of the voice call. <a href="https://www.jove.com/files/ftp_upload/60425/60425fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/60425/60425fig04.jpg" /> 
Figure 4: Stream of voice packets. Representation of the voice traffic exchanged during the call, measured at one of the AP VNFs. (Abbreviations: RX = receive, RX = transmit, RTP = real-time transport protocol). <a href="https://www.jove.com/files/ftp_upload/60425/60425fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/60425/60425fig05.jpg" /> 
Figure 5: Evolution of the network jitter during the call. Representation of the jitter experienced by the transmitted voice packets in the forward direction from one phone to the other. <a href="https://www.jove.com/files/ftp_upload/60425/60425fig5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Automated Deployment of an Internet Protocol Telephony Service on Unmanned Aerial Vehicles Using Network Functions Virtualization at JoVE.com

Automated Deployment of an Internet Protocol Telephony Service on Unmanned Aerial Vehicles Using Network Functions Virtualization

The objective of the described protocol is twofold: to configure a network functions virtualization environment using unmanned aerial vehicles as computational entities providing the underlying structure to execute virtualized network functions and to use this environment to support the automated deployment of a functional internet protocol telephony service over the aerial vehicles.

The Network Function Virtualization (NFV) paradigm is one of the key enabling technologies in the development of the 5th generation of mobile networks. ...

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Research

JoVE Journal

Engineering

7.9K Views.  Universidad Carlos III de Madrid. The objective of the described protocol is twofold: to configure a network functions virtualization environment using unmanned aerial vehicles as computational entities providing the underlying structure to execute virtualized network functions and to use this environment to support the automated deployment of a functional internet protocol telephony service over the aerial vehicles.

Video: Automated Deployment of an Internet Protocol Telephony Service on Unmanned Aerial Vehicles Using Network Functions Virtualization

Setting Limits on Supersymmetry Using Simplified Models

Experimental limits on supersymmetry and similar theories are difficult to set because of the enormous available parameter space and difficult to generalize because of the complexity of single points. Therefore, more phenomenological, simplified models are becoming popular for setting experimental limits, as they have clearer physical interpretations. The use of these simplified model limits to set a real limit on a concrete theory has not, however, been demonstrated. This paper recasts simplified model limits into limits on a specific and complete supersymmetry model, minimal supergravity. Limits obtained under various physical assumptions are comparable to those produced by directed searches. A prescription is provided for calculating conservative and aggressive limits on additional theories. Using acceptance and efficiency tables along with the expected and observed numbers of events in various signal regions, LHC experimental results can be recast in this manner into almost any theoretical framework, including nonsupersymmetric theories with supersymmetry-like signatures.

This paper demonstrates a protocol for recasting experimental simplified model limits into conservative and aggressive limits on an arbitrary new physics model. Publicly available LHC experimental results can be recast in this manner into limits on almost any new physics model with a supersymmetry-like signature.

Experimental limits on supersymmetry and similar theories are difficult to set because of the enormous available parameter space and difficult to ...

Experiments on Ultrasonic Lubrication Using a Piezoelectrically-assisted Tribometer and Optical Profilometer

Friction and wear are detrimental to engineered systems. Ultrasonic lubrication is achieved when the interface between two sliding surfaces is vibrated at a frequency above the acoustic range (20 kHz). As a solid-state technology, ultrasonic lubrication can be used where conventional lubricants are unfeasible or undesirable. Further, ultrasonic lubrication allows for electrical modulation of the effective friction coefficient between two sliding surfaces. This property enables adaptive systems that modify their frictional state and associated dynamic response as the operating conditions change. Surface wear can also be reduced through ultrasonic lubrication. We developed a protocol to investigate the dependence of friction force reduction and wear reduction on the linear sliding velocity between ultrasonically lubricated surfaces. A pin-on-disc tribometer was built which differs from commercial units in that a piezoelectric stack is used to vibrate the pin at 22 kHz normal to the rotating disc surface. Friction and wear metrics including effective friction force, volume loss, and surface roughness are measured without and with ultrasonic vibrations at a constant pressure of 1 to 4 MPa and three different sliding velocities: 20.3, 40.6, and 87 mm/sec. An optical profilometer is utilized to characterize the wear surfaces. The effective friction force is reduced by 62% at 20.3 mm/sec. Consistently with existing theories for ultrasonic lubrication, the percent reduction in friction force diminishes with increasing speed, down to 29% friction force reduction at 87 mm/sec. Wear reduction remains essentially constant (49%) at the three speeds considered.

We present a protocol for using a piezoelectrically-assisted tribometer and optical profilometer to investigate the dependence of ultrasonic wear and friction reduction on linear velocity, contact pressure, and surface properties.

Friction and wear are detrimental to engineered systems. Ultrasonic lubrication is achieved when the interface between two sliding surfaces is vibrated at ...

A Networked Desktop Virtual Reality Setup for Decision Science and Navigation Experiments with Multiple Participants

Investigating the interactions among multiple participants is a challenge for researchers from various disciplines, including the decision sciences and spatial cognition. With a local area network and dedicated software platform, experimenters can efficiently monitor the behavior of the participants that are simultaneously immersed in a desktop virtual environment and digitalize the collected data. These capabilities allow for experimental designs in spatial cognition and navigation research that would be difficult (if not impossible) to conduct in the real world. Possible experimental variations include stress during an evacuation, cooperative and competitive search tasks, and other contextual factors that may influence emergent crowd behavior. However, such a laboratory requires maintenance and strict protocols for data collection in a controlled setting. While the external validity of laboratory studies with human participants is sometimes questioned, a number of recent papers suggest that the correspondence between real and virtual environments may be sufficient for studying social behavior in terms of trajectories, hesitations, and spatial decisions. In this article, we describe a method for conducting experiments on decision-making and navigation with up to 36 participants in a networked desktop virtual reality setup (i.e., the Decision Science Laboratory or DeSciL). This experiment protocol can be adapted and applied by other researchers in order to set up a networked desktop virtual reality laboratory.

This paper describes a method for conducting multi-user experiments on decision-making and navigation using a networked computer laboratory.

Investigating the interactions among multiple participants is a challenge for researchers from various disciplines, including the decision sciences and ...

Behavior

Ground-level Unmanned Aerial System Imagery Coupled with Spatially Balanced Sampling and Route Optimization to Monitor Rangeland Vegetation

Rangeland ecosystems cover 3.6 billion hectares globally with 239 million hectares located in the United States. These ecosystems are critical for maintaining global ecosystem services. Monitoring vegetation in these ecosystems is required to assess rangeland health, to gauge habitat suitability for wildlife and domestic livestock, to combat invasive weeds, and to elucidate temporal environmental changes. Although rangeland ecosystems cover vast areas, traditional monitoring techniques are often time-consuming and cost-inefficient, subject to high observer bias, and often lack adequate spatial information. Image-based vegetation monitoring is faster, produces permanent records (i.e., images), may result in reduced observer bias, and inherently includes adequate spatial information. Spatially balanced sampling designs are beneficial in monitoring natural resources. A protocol is presented for implementing a spatially balanced sampling design known as balanced acceptance sampling (BAS), with imagery acquired from ground-level cameras and unmanned aerial systems (UAS). A route optimization algorithm is used in addition to solve the &#8216;travelling salesperson problem&#8217; (TSP) to increase time and cost efficiency. While UAS images can be acquired 2&#8211;3x faster than handheld images, both types of images are similar to each other in terms of accuracy and precision. Lastly, the pros and cons of each method are discussed and examples of potential applications for these methods in other ecosystems are provided.

The protocol presented in this paper utilizes route optimization, balanced acceptance sampling, and ground-level and unmanned aircraft system (UAS) imagery to efficiently monitor vegetation in rangeland ecosystems. Results from images obtained from ground-level and UAS methods are compared.

Rangeland ecosystems cover 3.6 billion hectares globally with 239 million hectares located in the United States. These ecosystems are critical for ...

Environment

Calibration of Vector Network Analyzer for Measurements in Radio Frequency Propagation Channels

In situ measurements of radio frequency (RF) spectrum activity provide insight into the physics of radio frequency wave propagation and validate existing and new spectrum propagation models. Both of these parameters are essential to supporting and preserving interference-free spectrum sharing, as spectrum use continues to increase. It is vital that such propagation measurements are accurate, reproducible, and free of artifacts and bias. Characterizing the gains and losses of components used in these measurements is vital to their accuracy. A vector network analyzer (VNA) is a well-established, highly accurate, and versatile piece of equipment that measures both magnitude and phase of signals, if properly calibrated. This article details the best practices for calibrating a VNA. Once calibrated, it can be used to accurately measure components of a correctly configured propagation measurement (or channel sounding) system or can be used as a measurement system itself.

This protocol describes best practices for calibrating a vector network analyzer prior to use as an accurate instrument, intended to measure components of a radio frequency propagation measurement test system.

In situ measurements of radio frequency (RF) spectrum activity provide insight into the physics of radio frequency wave propagation and validate existing ...

Integration of 5G Experimentation Infrastructures into a Multi-Site NFV Ecosystem

Network Function Virtualization (NFV) has been regarded as one of the key enablers for the 5th Generation of mobile networks, or 5G. This paradigm allows to reduce the dependence on specialized hardware to deploy telecommunications and vertical services. To this purpose, it relies on virtualization techniques to softwarize network functions, simplifying their development and reducing deployment time and costs. In this context, Universidad Carlos III de Madrid, Telef&#243;nica, and IMDEA Networks Institute have developed an NFV ecosystem inside 5TONIC, an open network innovation center focused on 5G technologies, enabling the creation of complex, close to reality experimentation scenarios across a distributed set of NFV infrastructures, which can be made available by stakeholders at different geographic locations. This article presents the protocol that has been defined to incorporate new remote NFV sites into the multi-site NFV ecosystem based on 5TONIC, describing the requirements for both the existing and the newly incorporated infrastructures, their connectivity through an overlay network architecture, and the steps necessary for the inclusion of new sites. The protocol is exemplified through the incorporation of an external site to the 5TONIC NFV ecosystem. Afterwards, the protocol details the verification steps required to validate a successful site integration. These include the deployment of a multi-site vertical service using a remote NFV infrastructure with Small Unmanned Aerial Vehicles (SUAVs). This serves to showcase the potential of the protocol to enable distributed experimentation scenarios.

The objective of the described protocol is to support the flexible incorporation of 5G experimentation infrastructures into a multi-site NFV ecosystem, through a VPN-based overlay network architecture. Moreover, the protocol defines how to validate the effectiveness of the integration, including a multi-site vertical service deployment with NFV-capable small aerial vehicles.

Network Function Virtualization (NFV) has been regarded as one of the key enablers for the 5th Generation of mobile networks, or 5G. This paradigm allows ...

Invasive Plant Biomass Assessment by Unmanned Aerial Vehicle Remote Sensing Data

Computer Vision-Based Biomass Estimation for Invasive Plants

We report on the detailed steps of a method to estimate the biomass of invasive plants based on UAV remote sensing and computer vision. To collect samples from the study area, we prepared a sample square assembly to randomize the sampling points. An unmanned aerial camera system was constructed using a drone and camera to acquire continuous RGB images of the study area through automated navigation. After completing the shooting, the aboveground biomass in the sample frame was collected, and all correspondences were labeled and packaged. The sample data was processed, and the aerial images were segmented into small images of 280 x 280 pixels to create an image dataset. A deep convolutional neural network was used to map the distribution of Mikania micrantha in the study area, and its vegetation index was obtained. The organisms collected were dried, and the dry weight was recorded as the ground truth biomass. The invasive plant biomass regression model was constructed using the K-nearest neighbor regression (KNNR)&#160;by extracting the vegetation index from the sample images as an independent variable and integrating it with the ground truth biomass as a dependent variable. The results showed that it was possible to predict the biomass of invasive plants accurately. An accurate spatial distribution map of invasive plant biomass was generated by image traversal, allowing precise identification of high-risk areas affected by invasive plants. In summary, this study demonstrates the potential of combining unmanned aerial vehicle remote sensing with&#160;machine learning techniques to estimate invasive plant biomass. It contributes significantly to the research of new technologies and methods for real-time monitoring of invasive plants and provides technical support for intelligent monitoring and hazard assessment at the regional scale.

Author Spotlight: UAV Remote Sensing for Efficient Invasive Plant Biomass Estimation

We report detailed procedures for an invasive plant biomass estimation method that utilizes data obtained from unmanned aerial vehicle (UAV) remote sensing to assess biomass and capture the spatial distribution of invasive species. This approach proves highly beneficial for conducting hazard assessment and early warning of invasive plants.

We report on the detailed steps of a method to estimate the biomass of invasive plants based on UAV remote sensing and computer vision. To collect samples ...

WebVR-Based Virtual Reality Laboratory System for Immersive Online Experiments

Online Virtual Reality Networked Control Laboratory Applied in Control Engineering Education

Online laboratories play an important role in engineering education. This work discusses a WebVR-based virtual laboratory system. The user enters the simulated laboratory environment through a virtual reality (VR) device and interacts with the experimental equipment, similar to hands-on experiments in a physical laboratory. In addition, the proposed system allows users to design their own control algorithms and observe the effects of different control parameters to enhance their understanding of the experiment. To illustrate the features of the proposed virtual laboratory, an example is provided in this paper, which is an experiment on a double inverted pendulum system. The experimental results show that the proposed system allows users to conduct experiments in an immersive and interactive manner and provides users with a complete experimental process from principal design to experimental operation. A solution is also provided to change any virtual laboratory into a WebVR-based virtual laboratory for education and training.

Author Spotlight: Enhancing Engineering Education via WebVR-Based Online Laboratories

This study describes a WebVR-based online virtual reality (VR) laboratory system that provides users with immersive and interactive experimentation capabilities supported by VR devices. The proposed system not only helps to enhance the realism of user participation in online experiments but is also applicable to a wide range of online laboratory frameworks.

Online laboratories play an important role in engineering education. This work discusses a WebVR-based virtual laboratory system. The user enters the ...

Optimized 3D Reconstruction and Motion Mapping for Remote AR-Assisted Surgery

Automatic Surgery in Transcatheter Aortic Valve Replacement Using Augmented Reality

Augmented Reality (AR) is in high demand in medical applications. The aim of the paper is to provide automatic surgery using AR for the Transcatheter Aortic Valve Replacement (TAVR). TAVR is the alternate medical procedure for open-heart surgery. TAVR replaces the injured valve with the new one using a catheter. In the existing model, remote guidance is given, while the surgery is not automated based on AR. In this article, we deployed a spatially aligned camera that is connected to a motor for the automation of image capture in the surgical environment. The camera tracks the 2D high-resolution image of the patient's heart along with the catheter testbed. These captured images are uploaded using the mobile app to a remote surgeon who is a cardiology expert. This image is utilized for the 3D reconstruction from 2D image tracking. This is viewed in a HoloLens like an emulator in a laptop. The surgeon can remotely inspect the 3D reconstructed images with additional transformation features such as rotation and scaling. These transformation features are enabled through hand gestures. The surgeon's guidance is transmitted to the surgical environment to automate the process in real-time scenarios. The catheter testbed in the surgical field is controlled by the hand gesture guidance of the remote surgeon. The developed prototype model demonstrates the effectiveness of remote surgical guidance through AR.

Author Spotlight: Revolutionizing Remote Surgery with Augmented Reality and Robotics for Enhanced Precision and Accessibility

This article presents the design and implementation of an automatic surgery module based on augmented reality (AR)- based 3D reconstruction. The system enables remote surgery by allowing surgeons to inspect reconstructed features and replicate surgical hand movements as if they were performing the surgery in close proximity.

Augmented Reality (AR) is in high demand in medical applications. The aim of the paper is to provide automatic surgery using AR for the Transcatheter ...

Medicine

Real-time Flight Control: Embedded Sensor Calibration and Data Acquisition

Source: Ella M. Atkins, Department of Aerospace Engineering, University of Michigan, Ann Arbor, MI
Overview
Autopilot allows aircraft to be stabilized using data collected from onboard sensors that measure the aircraft&#8217;s orientation, angular velocity, and airspeed. These quantities can be adjusted by the autopilot so that the aircraft automatically follows a flight plan from launch (takeoff) through recovery (landing). Similar sensor data is collected to control all types of aircraft, from large fixed-wing commercial transport aircraft to small-scale multiple-rotor helicopters, such as the quadcopter with four thruster units.
With inertial position and velocity captured by a sensor such as the Global Positioning System (GPS), the autopilot real-time flight control system enables a multicopter or fixed-wing aircraft to stabilize its attitude and airspeed to follow a prescribed trajectory. Sensor integration, calibration, data acquisition, and signal filtering are prerequisites for experiments in flight control.
Here we describe a sensor suite that provides the necessary data for flight control. Signal interfaces and data acquisition on two different embedded computer platforms are described, and sensor calibration is summarized. Single-channel moving average and median filters are applied to each data channel to reduce high-frequency signal noise and eliminate outliers.
In this experiment, data acquisition and sensor calibration for real-time flight control is demonstrated. Several published papers have described the principles of sensor data collection and control, and they have recently focused on sensors for small unmanned aerial vehicles (UAVs) [1-3].

Real-time Flight Control: Embedded Sensor Calibration

Source: Ella M. Atkins, Department of Aerospace Engineering, University of Michigan, Ann Arbor, MI
Overview
Autopilot allows aircraft to be stabilized ...