Autonomous docking using direct optimal control

We propose a method for performing autonomous docking of marine vessels using numerical optimal control. The task is framed as a dynamic positioning problem, with the addition of spatial constraints that ensure collision avoidance. The proposed method is an all-encompassing procedure for performing both docking, maneuvering, dynamic positioning and control allocation. In addition, we show that the method can be implemented as a real-time MPC-based algorithm on simulation results of a supply vessel.Comment: 12th IFAC Conference on Control Applications in Marine Systems, Robotics, and Vehicles (CAMS 2019). IFAC; Daejeon. 2019-09-18 - 2019-09-2

Temocillin in the treatment of Burkholderia cepacia infection in cystic fibrosis

AbstractBackgroundInfections due to Burkholderia cepacia complex (Bcc) strains increase morbidity and mortality in cystic fibrosis (CF). Some transplant centres reject Bcc infected patients. We reviewed the results in patients treated with i.v temocillin.MethodsTwenty-three patients who received 38 courses of temocillin (1988–1998) were identified from the CF database at Royal Brompton Hospital. In three patients' data were inadequate; therefore analysis was done in 20. Outcome was measured as improvement, deterioration or no change (compared to admission) in the following categories: clinical (temperature, dyspnoea, sputum volume, chest pain), physiological (FEV1, FVC, oxygen saturation) and inflammatory markers (WBC, ESR, CRP). Patients who improved in two categories were classified as having improved. Antibiotic sensitivities and outcome were recorded.ResultsIn 18 of 32 courses (56.25%) improvement occurred. The organism (Bcc) in eight patients' sputum became resistant (three died). The antibiotics was changed in five patients with Bcc strains sensitive to temocillin because of no improvement and one patient due to allergy (rash). The average time to the next i.v antibiotic was 41 days. Eight patients died (in three the Bcc strain was resistant to temocillin). Fourteen patients with Bcc were transplanted and eight patients survived. Another patient who developed Bcc infection post-operatively, failing to respond to temocillin.ConclusionsThese results suggest the potential benefit of i.v temocillin in CF patients with Bcc for exacerbations and at the time of transplantation

Combining system identification with reinforcement learning-based MPC

In this paper we propose and compare methods for combining system identification (SYSID) and reinforcement learning (RL) in the context of data-driven model predictive control (MPC). Assuming a known model structure of the controlled system, and considering a parametric MPC, the proposed approach simultaneously: a) Learns the parameters of the MPC using RL in order to optimize performance, and b) fits the observed model behaviour using SYSID. Six methods that avoid conflicts between the two optimization objectives are proposed and evaluated using a simple linear system. Based on the simulation results, hierarchical, parallel projection, nullspace projection, and singular value projection achieved the best performance.Comment: Accepted to the IFAC202

Warm-Started Optimized Trajectory Planning for ASVs

We consider warm-started optimized trajectory planning for autonomous surface vehicles (ASVs) by combining the advantages of two types of planners: an A* implementation that quickly finds the shortest piecewise linear path, and an optimal control-based trajectory planner. A nonlinear 3-degree-of-freedom underactuated model of an ASV is considered, along with an objective functional that promotes energy-efficient and readily observable maneuvers. The A* algorithm is guaranteed to find the shortest piecewise linear path to the goal position based on a uniformly decomposed map. Dynamic information is constructed and added to the A*-generated path, and provides an initial guess for warm starting the optimal control-based planner. The run time for the optimal control planner is greatly reduced by this initial guess and outputs a dynamically feasible and locally optimal trajectory.Comment: Accepted to the 12th IFAC Conference on Control Applications in Marine Systems, Robotics, and Vehicles (CAMS 2019

Trajectory Planning and Control for Automatic Docking of ASVs with Full-Scale Experiments

We propose a method for performing automatic docking of a small autonomous surface vehicle (ASV) by interconnecting an optimization-based trajectory planner with a dynamic positioning (DP) controller for trajectory tracking. The trajectory planner provides collision-free trajectories by considering a map with static obstacles, and produces feasible trajectories through inclusion of a mathematical model of the ASV and its actuators. The DP controller tracks the time-parametrized position, velocity and acceleration produced by the trajectory planner using proportional-integral-derivative feedback with velocity and acceleration feed forward. The method's performance is tested on a small ASV in confined waters in Trondheim, Norway. The ASV performs collision-free docking maneuvers with respect to static obstacles when tracking the generated reference trajectories and achieves successful docking.Comment: 12 pages, 7 figures. Accepted to the IFAC World Congress 202

Autonomous subsea intervention (SEAVENTION)

This paper presents the main results and latest developments in a 4-year project called autonomous subsea intervention (SEAVENTION). In the project we have developed new methods for autonomous inspection, maintenance and repair (IMR) in subsea oil and gas operations with Unmanned Underwater Vehicles (UUVs). The results are also relevant for offshore wind, aquaculture and other industries. We discuss the trends and status for UUV-based IMR in the oil and gas industry and provide an overview of the state of the art in intervention with UUVs. We also present a 3-level taxonomy for UUV autonomy: mission-level, task-level and vehicle-level. To achieve robust 6D underwater pose estimation of objects for UUV intervention, we have developed marker-less approaches with input from 2D and 3D cameras, as well as marker-based approaches with associated uncertainty. We have carried out experiments with varying turbidity to evaluate full 6D pose estimates in challenging conditions. We have also devised a sensor autocalibration method for UUV localization. For intervention, we have developed methods for autonomous underwater grasping and a novel vision-based distance estimator. For high-level task planning, we have evaluated two frameworks for automated planning and acting (AI planning). We have implemented AI planning for subsea inspection scenarios which have been analyzed and formulated in collaboration with the industry partners. One of the frameworks, called T-REX demonstrates a reactive behavior to the dynamic and potentially uncertain nature of subsea operations. We have also presented an architecture for comparing and choosing between mission plans when new mission goals are introduced.publishedVersio

Role of exosomal micrornas in regulating the immune response to lung cancer

Lung cancer is one of the most frequent malignant neoplasms and the main cause of cancer death. Despite medical advances, survival remains low in non-small cell lung cancer (NSCLC), the commonest type. Macrophages play a substantial role in tumour progression because of their plasticity during activation and tumour infiltration. M1 polarised macrophages are associated with increase survival in lung cancer but tumour-associated macrophages (TAM) are distinct in their potential to promote or hinder tumour development. There has been increasing recognition of molecular drivers of cancer and amongst them, exosomes are thought to modulate the wider tumour micro-environment. Exosomes are extracellular vesicles secreted by all cell types and facilitate remodelling, immune escape promotion and tumour development in the tumour microenvironment. Exosomes can transport a diverse cargo of RNA, DNA, and protein. MicroRNAs form a potentially important exosomal cargo which may affect entire cellular pathways of recipient cells, such as macrophages. Identifying, which miRNAs are associated with these processes may be essential in management of lung cancer patients. I propose that TAMs are affected by exosomes generated by tumours, and this affects their ability to respond to the tumour. The hypothesis is that differentially expressed specific exosomal miRNAs derived from NSCLC tumour alters the phenotype of macrophages resulting in immune regulation of macrophages in the tumour microenvironment. In this project, I characterised tumour derived exosomes (TDE) and their paired normal lung tissue derived exosomes (NDE) and shown that I can sequence their microRNA cargo. The differential expression testing with DESeq2 of TDE and NDE identified 465 differentially expressed miRNAs. Eight miRNAs (miR-21-5p, miR-100-5p, miR-101-3p, miR-126a-5p, miR-133a-3p, miR-149-5p, miR193a-3p, and miR-205-5p) were statistically significantly differentially expressed and involved in signaling pathways related to polarisation of macrophages towards the anti-inflammatory phenotype M2. Those pathways were PI3K/Akt/mTOR, TLRs/NF-κB, JAK/STAT and JNK/MAPK. I subsequently compared and correlated the targeted mRNA of the TDE versus NDE differentially expressed miRNAs with the differentially expressed mRNA from tumour associated macrophages (TAM) and non-tumour associated macrophages (NTAM). Eleven miRNAs (miR-1-3p, miR-105-5p, miR-126a-3p, miR-16-5p, miR-193a-3p, miR-21-5p, miR2682-5p, miR-30a-3p, miR-34a-5p, miR-503-5p, miR-9-5p) were identified. The dysregulated mRNA and their signaling pathways were like the affected pathways from differentially expressed miRNAs in the TDE and NDE comparison group. These were PI3K/Akt/mTOR, TLRs/NF-κB and JAKSTAT signaling pathway. I subsequently exposed in vitro derived macrophages to TDE and their paired NDE. My results indicated that macrophages exposed to TDE had a milder inflammatory profile (dysregulation of IL6, SOCS-1, Serpin-B1 and CCL18) than those exposed to paired NDE. These macrophages were subsequently subjected to Next Generation Sequencing (NGS)/RNA to evaluate their transcriptome (mRNA and microRNA) expression. The aim was to establish if miRNA cargo can affect macrophage’s phenotype. The miRNA signature of those macrophages showed one significant differentially expressed miRNA (miR-451a) which is known to be dysregulated in cancer and has anti-inflammatory effect. My work has potential impact in identifying the effects of tumour derived exosomes and particularly their miRNAs in macrophage’s polarisation in the tumour microenvironment