Anna Lito Michala

Solving the task variant allocation problem in distributed robotics

We consider the problem of assigning software processes (or tasks) to hardware processors in distributed robotics environments. We introduce the notion of a task variant, which supports the adaptation of software to specific hardware configurations. Task variants facilitate the trade-off of functional quality versus the requisite capacity and type of target execution processors. We formalise the problem of assigning task variants to processors as a mathematical model that incorporates typical constraints found in robotics applications; the model is a constrained form of a multi-objective, multi-dimensional, multiple-choice knapsack problem. We propose and evaluate three different solution methods to the problem: constraint programming, a constructive greedy heuristic and a local search metaheuristic. Furthermore, we demonstrate the use of task variants in a real instance of a distributed interactive multi-agent navigation system, showing that our best solution method (constraint programming) improves the system’s quality of service, as compared to the local search metaheuristic, the greedy heuristic and a randomised solution, by an average of 16, 31 and 56% respectively.

An intelligent system for vessels structural reliability evaluation

An intelligent system is proposed within INCASS (Inspection Capabilities for Enhanced Ship Safety) project for evaluating ship structural reliability and assisting in fatigue damage and structure response assessment. The system combines hydrodynamic, finite element and structural reliability models.. The hydrodynamic analysis model is not discussed in this paper. The finite element model input is a mesh for the mid-ship part of the vessel. Finally, the in-house structural reliability model input is the calculated output of the previous model as well as models for estimating crack development and propagation, corrosion growth and fatigue loading. The output includes the probability of failure for all the investigated components versus time which can be used to assess safe operation through the developed decision support software. The database can receive information from various sources including inspection and robotic systems data. The case study of a capsize bulk carrier the presents structural evaluation process.