Safe and Distributed Kinodynamic Replanning for Vehicular Networks

This work deals with the problem of planning collision-free motions for multiple communicating vehicles that operate in the same, partially-observable environment in real-time. A challenging aspect of this problem is how to utilize communication so that vehicles do not reach states from which collisions cannot be avoided due to second-order motion constraints. This paper initially shows how it is possible to provide theoretical safety guarantees with a priority-based coordination scheme. Safety means avoiding collisions with obstacles and between vehicles. This notion is also extended to include the retainment of a communication network when the vehicles operate as a networked team. The paper then progresses to extend this safety framework into a fully distributed communication protocol for real-time planning. The proposed algorithm integrates sampling-based motion planners with message-passing protocols for distributed constraint optimization. Each vehicle uses the motion planner to generate candidate feasible trajectories and the message-passing protocol for selecting a safe and compatible trajectory. The existence of such trajectories is guaranteed by the overall approach. The theoretical results have also been experimentally confirmed with a distributed simulator built on a cluster of processors and using applications such as coordinated exploration. Furthermore, experiments show that the distributed protocol has better scalability properties when compared against the priority-based scheme. Part of the material presented in this paper has appeared in two conference publications: “A Decentralized Planner that Guarantees the Safety of Communicating Vehicles with Complex Dynamics that Replan Online” at IROS 2007 and “A Distributed Protocol for Safe Real-Time Planning of Communicating Vehicles with Second-Order Dynamics” at ROBOCOMM 2007.     

Valuating the Receiving Waters of Urban Wastewater Systems through a Stakeholder-based Approach

The valuation of ecological services in European aquatic ecosystems is increasingly deemed to be an essential element for the integrated management concept pursued by the Water Framework Directive (2000/60/EC). However, the assessment methods are often doubted for their objectivity and transparency when based on the elicitation of stated preferences. The current research attempted to explicitly focus on the biases linked with the stakeholders participating in assessing methods operating with stated preferences. The most significant stakeholder groups were classified in three broad teams of Experts, Decision Makers and Affected Professions. The three teams' preferences were in turn assessed in economic and non-economic terms for the accentuation of the high fluctuation among the findings, and the threatening biases emerged in the sourcing of stated preference methods. The wastewater treatment plant in Athens, Greece and Saronikos Bay offered a sound case study.     

Antibody covalent immobilization on carbon nanotubes and assessment of antigen binding

Controlling the covalent bonding of antibodies onto functionalized carbon nanotubes is a key step in the design and preparation of nanotube-based conjugates for targeting cancer cells. For this purpose, an anti-MUC1 antibody (Ab) is linked to both multi-walled (MWCNTs) and double-walled carbon nanotubes (DWCNTs) using different synthetic strategies. The presence of the Ab attached to the nanotubes is confirmed by gel electrophoresis and thermogravimetric analysis. Most importantly, molecular recognition of the antigen by surface plasmon resonance is able to determine similar Ab binding capacities for both Ab-DWCNTs and Ab-MWCNTs. These results are very relevant for the design of future receptor-targeting strategies using chemically functionalized carbon nanotubes.     

Removal of As(V) from wastewaters by chemically modified fungal biomass

Biosorption has been demonstrated to be a useful alternative to conventional treatment systems for the removal of toxic metals from dilute aqueous solution. The objective of this paper was to examine the main aspects of a possible strategy for the removal of arsenates, employing P. chrysogenum biomass. The pretreatment of biomass with common surfactants (as hexadecyl-trimethylammonium bromide and dodecylamine) and a cationic polyelectrolyte was found to improve the biosorption efficiency. The initial biomass showed a relative low affinity for metallic anions, whereas with the application of modified samples a significant uptake of arsenic was observed. Sorption data were well described by typical Langmuir and Freundlich adsorption isotherms. Promising results were obtained in laboratory experiments and effective As(V) removals were observed.