Adding Sessions to BPEL

By considering an essential subset of the BPEL orchestration language, we define SeB, a session based style of this subset. We discuss the formal semantics of SeB and we present its main properties. We use a new approach to address the formal semantics, based on a translation into so-called control graphs. Our semantics handles control links and addresses the static semantics that prescribes the valid usage of variables. We also provide the semantics of collections of networked services. Relying on these semantics, we define precisely what is meant by interaction safety, paving the way to the formal analysis of safe interactions between BPEL services

Reachability-based Trajectory Design with Neural Implicit Safety Constraints

Generating safe motion plans in real-time is a key requirement for deploying robot manipulators to assist humans in collaborative settings. In particular, robots must satisfy strict safety requirements to avoid self-damage or harming nearby humans. Satisfying these requirements is particularly challenging if the robot must also operate in real-time to adjust to changes in its environment.This paper addresses these challenges by proposing Reachability-based Signed Distance Functions (RDFs) as a neural implicit representation for robot safety. RDF, which can be constructed using supervised learning in a tractable fashion, accurately predicts the distance between the swept volume of a robot arm and an obstacle. RDF's inference and gradient computations are fast and scale linearly with the dimension of the system; these features enable its use within a novel real-time trajectory planning framework as a continuous-time collision-avoidance constraint. The planning method using RDF is compared to a variety of state-of-the-art techniques and is demonstrated to successfully solve challenging motion planning tasks for high-dimensional systems faster and more reliably than all tested methods

Serving Time: Real-Time, Safe Motion Planning and Control for Manipulation of Unsecured Objects

A key challenge to ensuring the rapid transition of robotic systems from the industrial sector to more ubiquitous applications is the development of algorithms that can guarantee safe operation while in close proximity to humans. Motion planning and control methods, for instance, must be able to certify safety while operating in real-time in arbitrary environments and in the presence of model uncertainty. This paper proposes Wrench Analysis for Inertial Transport using Reachability (WAITR), a certifiably safe motion planning and control framework for serial link manipulators that manipulate unsecured objects in arbitrary environments. WAITR uses reachability analysis to construct over-approximations of the contact wrench applied to unsecured objects, which captures uncertainty in the manipulator dynamics, the object dynamics, and contact parameters such as the coefficient of friction. An optimization problem formulation is presented that can be solved in real-time to generate provably-safe motions for manipulating the unsecured objects. This paper illustrates that WAITR outperforms state of the art methods in a variety of simulation experiments and demonstrates its performance in the real-world.Comment: 8 pages, 3 figures. For project page with code, videos, and supplementary appendices, see https://roahmlab.github.io/waitr-dev/. arXiv admin note: text overlap with arXiv:2301.1330

A Semantically Rich Approach for Collaborative Model Edition

International audienceWe propose a novel approach and tool for collaborative software engineering and development. In model-based software engineering, the underlying data structure is a complex, directed and labeled graph. Collaborative engineering requires that developers be able to copy the graph, make independent changes, compare them, detect conflicts, and merge non-conflicting graphs. To support different collaboration and development styles requires a very flexible toolset. Worldwide, loosely-coupled development teams require the support of large-scale networks of users, possibly disconnected, in a decentralised fashion. No matter how the graph replicas evolve, they must eventually converge. We describe and evaluate C-Praxis, a tool that satisfies these requirements

Can't Touch This: Real-Time, Safe Motion Planning and Control for Manipulators Under Uncertainty

Ensuring safe, real-time motion planning in arbitrary environments requires a robotic manipulator to avoid collisions, obey joint limits, and account for uncertainties in the mass and inertia of objects and the robot itself. This paper proposes Autonomous Robust Manipulation via Optimization with Uncertainty-aware Reachability (ARMOUR), a provably-safe, receding-horizon trajectory planner and tracking controller framework for robotic manipulators to address these challenges. ARMOUR first constructs a robust controller that tracks desired trajectories with bounded error despite uncertain dynamics. ARMOUR then uses a novel recursive Newton-Euler method to compute all inputs required to track any trajectory within a continuum of desired trajectories. Finally, ARMOUR over-approximates the swept volume of the manipulator; this enables one to formulate an optimization problem that can be solved in real-time to synthesize provably-safe motions. This paper compares ARMOUR to state of the art methods on a set of challenging manipulation examples in simulation and demonstrates its ability to ensure safety on real hardware in the presence of model uncertainty without sacrificing performance. Project page: https://roahmlab.github.io/armour/.Comment: 20 pages, 6 figure

Prothrombotic Hemostasis Disturbances in Patients with Severe COVID-19:Individual daily data

This data article accompanies the manuscript entitled: "Prothrombotic Disturbances of hemostasis of Patients with Severe COVID-19: a Prospective Longitudinal Observational Cohort Study" submitted to by the same authors. We report temporal changes of plasma levels of an extended set of laboratory parameters during the ICU stay of the 21 COVID-19 patients included in the monocentre cohort: CRP, platelet count, prothrombin time; Clauss fibrinogen and clotting factors II, V and VIII levels, D-dimers, antithrombin activity, protein C, free protein S, total and free tissue factor pathway inhibitor, PAI-1 levels, von Willebrand factor antigen and activity, ADAMTS-13 (plasma levels); and of two integrative tests of coagulation (thrombin generation with ST Genesia) and fibrinolysis (global fibrinolytic capacity - GFC). Regarding hemostasis, we used double-centrifuged frozen citrated plasma prospectively collected after daily performance of usual coagulation tests. Demographic and clinical characteristics of patients and thrombotic and hemorrhagic complications were also collected from patient's electronic medical reports