7 research outputs found
A Customizable Conflict Resolution and Attribute-Based Access Control Framework for Multi-Robot Systems
As multi-robot systems continue to advance and become integral to various
applications, managing conflicts and ensuring secure access control are
critical challenges that need to be addressed. Access control is essential in
multi-robot systems to ensure secure and authorized interactions among robots,
protect sensitive data, and prevent unauthorized access to resources. This
paper presents a novel framework for customizable conflict resolution and
attribute-based access control in multi-robot systems for ROS 2 leveraging the
Hyperledger Fabric blockchain. We introduce an attribute-based access control
(ABAC) Fabric-ROS 2 bridge to enable secure communication and control between
users and robots. By defining conflict resolution policies based on task
priorities, robot capabilities, and user-defined constraints, our framework
offers a flexible way to resolve conflicts. Additionally, it incorporates
attribute-based access control, granting access rights based on user and robot
attributes. ABAC offers a modular approach to control access compared to
existing access control approaches in ROS 2, such as SROS2. Through this
framework, multi-robot systems can be managed efficiently, securely, and
adaptably, ensuring controlled access to resources and managing conflicts. Our
experimental evaluation shows that our framework marginally improves latency
and throughput over exiting Fabric and ROS 2 integration solutions. At higher
network load, it is the only solution to operate reliably without a diverging
transaction commitment latency. We also demonstrate how conflicts arising from
simultaneous control or a robot by two users are resolved in real-time and
motion distortion is effectively eliminated
Decentralized Vision-Based Byzantine Agent Detection in Multi-Robot Systems with IOTA Smart Contracts
Multiple opportunities lie at the intersection of multi-robot systems and
distributed ledger technologies (DLTs). In this work, we investigate the
potential of new DLT solutions such as IOTA, for detecting anomalies and
byzantine agents in multi-robot systems in a decentralized manner. Traditional
blockchain approaches are not applicable to real-world networked and
decentralized robotic systems where connectivity conditions are not ideal. To
address this, we leverage recent advances in partition-tolerant and
byzantine-tolerant collaborative decision-making processes with IOTA smart
contracts. We show how our work in vision-based anomaly and change detection
can be applied to detecting byzantine agents within multiple robots operating
in the same environment. We show that IOTA smart contracts add a low
computational overhead while allowing to build trust within the multi-robot
system. The proposed approach effectively enables byzantine robot detection
based on the comparison of images submitted by the different robots and
detection of anomalies and changes between them
Distributed Robotic Systems in the Edge-Cloud Continuum with ROS 2: a Review on Novel Architectures and Technology Readiness
Robotic systems are more connected, networked, and distributed than ever. New
architectures that comply with the \textit{de facto} robotics middleware
standard, ROS\,2, have recently emerged to fill the gap in terms of hybrid
systems deployed from edge to cloud. This paper reviews new architectures and
technologies that enable containerized robotic applications to seamlessly run
at the edge or in the cloud. We also overview systems that include solutions
from extension to ROS\,2 tooling to the integration of Kubernetes and ROS\,2.
Another important trend is robot learning, and how new simulators and cloud
simulations are enabling, e.g., large-scale reinforcement learning or
distributed federated learning solutions. This has also enabled deeper
integration of continuous interaction and continuous deployment (CI/CD)
pipelines for robotic systems development, going beyond standard software unit
tests with simulated tests to build and validate code automatically. We discuss
the current technology readiness and list the potential new application
scenarios that are becoming available. Finally, we discuss the current
challenges in distributed robotic systems and list open research questions in
the field
Comparison of total phenolic and antioxidant activity of different Mentha spicata and M. longifolia accessions
This study investigated total phenolic and antioxidant activity of five Iranian mint accessions from two different species, Mentha spicata L. (Mzin1, Mzin3 and Mzin8) and M. longifolia L. (Mzin5 and Mzin6). The content of total phenolics (mg tannic acid equivalent per g dry weight of the sample) differed from 50.1 in Mzin3 to 67.2 in Mzin6. The highest percent radical scavenging activity was observed with Mzin6 at all concentrations studied (50, 100, 250, and 500Â ppm). Peroxide value of sunflower oil containing Mzin5 and Mzin6 was the lowest among the mint accessions and almost equivalent to that of butylated hydroxytoluene at 200Â ppm concentration. In overall, M. longifolia was superior to M. spicata, as determined by two model systems, indicating its potential use as a natural source of dietary antioxidant
MyoRing implantation in keratoconic patients: 3 years follow-up data
Purpose: To evaluate long-term follow-up data on implantation of a full-ring intra-corneal implant (MyoRing) for management of keratoconus.
Methods: A total of 40 keratoconic eyes of 37 consecutive patients who had undergone MyoRing implantation using the Pocket Maker microkeratome (Dioptex, GmbH, Linz, Austria) and completed 3 years of follow-up appointments were included in this retrospective study. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refraction and keratometry (K) readings were measured and evaluated preoperatively, and 3 years, postoperatively.
Results: No intraoperative complications were observed in this case series. Three years postoperatively, there was a significant improvement in UDVA, CDVA, K readings, spherical equivalent (SE), and manifest sphere and cylinder (P < 0.05 for all comparisons). UDVA was significantly improved from 1.14 ± 0.27 to 0.30 ± 0.21 LogMAR (P = 0.001), CDVA was also improved from 0.52 ± 0.23 to 0.18 ± 0.12 LogMAR (P = 0.001), SE was decreased by 4.35 diopters (D) and average keratometric values were reduced by 2.34 D (P = 0.001). Overall, 81% of subjects were moderately to highly satisfied 3 years after surgery and 64.90% agreed to have the fellow eye implanted with MyoRing.
Conclusion: MyoRing implantation using the Pocket Maker microkeratome was found to be a minimally invasive procedure for improving visual acuity and refraction in the majority of the patients with keratoconus