An energy-aware architecture : a practical implementation for autonomous underwater vehicles

Energy awareness, fault tolerance and performance estimation are important aspects for extending the autonomy levels of today’s autonomous vehicles. Those are related to the concepts of survivability and reliability, two important factors that often limit the trust of end users in conducting large-scale deployments of such vehicles. With the aim of preparing the way for persistent autonomous operations this work focuses its efforts on investigating those effects on underwater vehicles capable of long-term missions. A novel energy-aware architecture for autonomous underwater vehicles (AUVs) is presented. This, by monitoring at runtime the vehicle’s energy usage, is capable of detecting and mitigating failures in the propulsion subsystem, one of the most common sources of mission-time problems. Furthermore it estimates the vehicle’s performance when operating in unknown environments and in the presence of external disturbances. These capabilities are a great contribution for reducing the operational uncertainty that most underwater platforms face during their deployment. Using knowledge collected while conducting real missions the proposed architecture allows the optimisation of on-board resource usage. This improves the vehicle’s effectiveness when operating in unknown stochastic scenarios or when facing the problem of resource scarcity. The architecture has been implemented on a real vehicle, Nessie AUV, used for real sea experiments as part of multiple research projects. These gave the opportunity of evaluating the improvements of the proposed system when considering more complex autonomous tasks. Together with Nessie AUV, the commercial platform IVER3 AUV has been involved in the evaluating the feasibility of this approach. Results and operational experience, gathered both in real sea scenarios and in controlled environment experiments, are discussed in detail showing the benefits and the operational constraints of the introduced architecture, alongside suggestions for future research directions

Putative role of circulating human papillomavirus DNA in the development of primary squamous cell carcinoma of the middle rectum: a case report

Here we present the case of a patient affected by rectal squamous cell carcinoma in which we demonstrated the presence of Human Papillomavirus (HPV) by a variety of techniques. Collectively, the virus was detected not only in the tumor but also in some regional lymph nodes and in non-neoplastic mucosa of the upper tract of large bowel. By contrast, it was not identifiable in its common sites of entry, namely oral and ano-genital region. We also found HPV DNA in the plasma-derived exosome. Next, by in vitro studies, we confirmed the capability of HPV DNA-positive exosomes, isolated from the supernatant of a HPV DNA positive cell line (CaSki), to transfer its DNA to human colon cancer and normal cell lines. In the stroma nearby the tumor mass we were able to demonstrate the presence of virus DNA in the stromal compartment, supporting its potential to be transferred from epithelial cells to the stromal ones. Thus, this case report favors the notion that human papillomavirus DNA can be vehiculated by exosomes in the blood of neoplastic patients and that it can be transferred, at least in vitro, to normal and neoplastic cells. Furthermore, we showed the presence of viral DNA and RNA in pluripotent stem cells of non-tumor tissue, suggesting that after viral integration (as demonstrated by p16 and RNA in situ hybridization positivity), stem cells might have been activated into cancer stem cells inducing neoplastic transformation of normal tissue through the inactivation of p53, p21, and Rb. It is conceivable that the virus has elicited its oncogenic effect in this specific site and not elsewhere, despite its wide anatomical distribution in the patient, for a local condition of immune suppression, as demonstrated by the increase of T-regulatory (CD4/CD25/FOXP3 positive) and T-exhausted (CD8/PD-1positive) lymphocytes and the M2 polarization (high CD163/CD68 ratio) of macrophages in the neoplastic microenvironment. It is noteworthy that our findings depicted a static picture of a long-lasting dynamic process that might evolve in the development of tumors in other anatomical sites. Copyright © 2019 Ambrosio, Vernillo, De Carolis, Carducci, Mundo, Ginori, Rocca, Nardone, Lucenti Fei, Carfagno, Lazzi, Cricca and Tosi

Dynamically extending planning models using an ontology

In this paper we couple a deterministic planner with an ontology, in order to adapt to new discoveries during plan execution and to reason about the affordances that are available to the planner as the set of known objects is updated. This allows us to extend the planning agent’s functionality during execution. We use as an example planning for persistent autonomous behaviour in underwater vehicles. Planning in this scenario takes place in a symbolic model of the environment, simulating sequences of possible decisions. Ensuring that the simulation remains robust requires careful matching of the model to the real world, including dynamically updating the model from continuous sensing actions. We describe how our system constructs an initial state for planning, using the ontology; how the ontology is also used to determine the results of each action performed by the planner; and finally demonstrate the performance of the system in a simulation, in which two AUVs are required to cooperate in an unknown environment, demonstrating that with additional reasoning the planning system is able to make new efficient choices, taking advantage of the environment in new ways

Dynamically extending planning models using an ontology

In this paper we couple a deterministic planner with an ontology, in order to adapt to new discoveries during plan execution and to reason about the affordances that are available to the planner as the set of known objects is updated. This allows us to extend the planning agent’s functionality during execution. We use as an example planning for persistent autonomous behaviour in underwater vehicles. Planning in this scenario takes place in a symbolic model of the environment, simulating sequences of possible decisions. Ensuring that the simulation remains robust requires careful matching of the model to the real world, including dynamically updating the model from continuous sensing actions. We describe how our system constructs an initial state for planning, using the ontology; how the ontology is also used to determine the results of each action performed by the planner; and finally demonstrate the performance of the system in a simulation, in which two AUVs are required to cooperate in an unknown environment, demonstrating that with additional reasoning the planning system is able to make new efficient choices, taking advantage of the environment in new ways

Low-cost energy measurement and estimation for autonomous underwater vehicles

Abstract—This work introduces a low-cost energy measure-ment method and proposes a simple linear model to estimate the vehicle energy consumption when navigating a given trajectory. Experimental results on Nessie VII AUV show that the developed system can be used to measure the energy used during the vehicle’s operations with a good confidence level. Moreover the proposed estimation model can be trained using a simple calibration procedure each time the environmental conditions change or the vehicle’s configuration is altered. The proposed solution is suited to real-time use on low-power embedded devices. The limited use of computation resources mean that this method is well suited for supporting navigation planning and motion control. I