Coverage Path Planning with Real‐time Replanning and Surface Reconstruction for Inspection of Three‐dimensional Underwater Structures using Autonomous Underwater Vehicles

We present a novel method for planning coverage paths for inspecting complex structures on the ocean floor using an autonomous underwater vehicle (AUV). Our method initially uses a 2.5‐dimensional (2.5D) prior bathymetric map to plan a nominal coverage path that allows the AUV to pass its sensors over all points on the target area. The nominal path uses a standard mowing‐the‐lawn pattern in effectively planar regions, while in regions with substantial 3D relief it follows horizontal contours of the terrain at a given offset distance. We then go beyond previous approaches in the literature by considering the vehicle's state uncertainty rather than relying on the unrealistic assumption of an idealized path execution. Toward that end, we present a replanning algorithm based on a stochastic trajectory optimization that reshapes the nominal path to cope with the actual target structure perceived in situ. The replanning algorithm runs onboard the AUV in real time during the inspection mission, adapting the path according to the measurements provided by the vehicle's range‐sensing sonars. Furthermore, we propose a pipeline of state‐of‐the‐art surface reconstruction techniques we apply to the data acquired by the AUV to obtain 3D models of the inspected structures that show the benefits of our planning method for 3D mapping. We demonstrate the efficacy of our method in experiments at sea using the GIRONA 500 AUV, where we cover part of a breakwater structure in a harbor and an underwater boulder rising from 40 m up to 27 m depth.     

The proportional coalitional Shapley value

We propose a modification of the Shapley value for monotonic games with a coalition structure. The resulting coalitional value is a twofold extension of the Shapley value in the following sense: (1) the amount obtained by any union coincides with the Shapley value of the union in the quotient game; and (2) the players of the union share this amount proportionally to their Shapley value in the original game (i.e., without unions). We provide axiomatic characterizations of this value close to those existing in the literature for the Owen value and include applications to coalition formation in bankruptcy and voting problems.     

Integral assessment of pollution in the Suquía River (Córdoba, Argentina) as a contribution to lotic ecosystem restoration programs

The Suquía River lower-middle basin (Córdoba, Argentina) is subject to a strong anthropic impact because it receives pollutants from different sources (industries, wastewaters, heavy traffic, agricultural land use, etc.) We have assessed the degree of watershed degradation of Suquía River lower-middle sections through the analysis of different ecosystem compartments (air, water, riparian soil, sediments and biota), in order to provide useful data to be considered in future river restoration programs. Four study sites were selected along the river (La Calera city, Córdoba city, Corazón de María village and Río Primero city) which were sampled during the low- and high-water flow periods. We analyzed: a) chemical and physical characteristics of water, sediments, and riparian soil; b) heavy metal content of water and sediments, and c) semi-volatile organic compounds in air. Besides, pollutant bioindicators such as fish assemblages, lichens (Usnea amblyoclada), vascular plants (Tradescantia pallida), and microorganisms (fecal coliform and Escherichia coli) were used to further assess the status of the river. All analyzed ecological compartments were affected by water pollution, particularly, fish assemblages, sediments and riparian soils by heavy metal and coliform bacteria. Moreover, we detected a possible contribution of sulfur and a high pollutant content in air that merit further research about other air-water exchanges. Accordingly, we strongly suggest that an action to restore or remediate the anthropic effect on the Suquía River be extended to all possible compartments along the river.     

Frequency tuning in electromagnetic bandgap nonlinear transmission lines

Frequency tuning in stopband filters based on nonlinear transmission lines is demonstrated for the first time. The structure is an electromagnetic bandgap (EBG) coplanar waveguide reflector periodically loaded with varactor diodes, acting as tuning elements. By varying the capacitance of the diodes the phase velocity can be tailored, the result being a wide tuning range for the central frequency of the rejected band. It was also found that the EBG-based reflector is able to inhibit harmonic generation under large-signal driving conditions.     

Incidence and outcome of hepatic veno-occlusive disease after blood or marrow transplantation: a prospective cohort study of the European Group for Blood and Marrow Transplantation. European Group for Blood and Marrow Transplantation Chronic Leukemia Working Party

To determine the incidence and outcome of hepatic veno-occlusive disease (VOD) after blood or marrow transplantation (BMT), we prospectively evaluated all consecutive patients receiving a BMT during a 6-month period in participating EBMT centers. All of them were evaluated for occurrence of VOD according to previously defined clinical criteria. The clinical course, outcome, value of prophylactic and therapeutic interventions, and the influence of previously described risk factors were analyzed. During the study period, 1,652 BMT were performed in 73 centers. VOD was diagnosed in 87 patients (5.3%; 95% confidence interval [CI], 4.2% to 6.4%). Fifty-six of 631 allogeneic BMT (8.9%) and 31 of 1,010 autologous BMT (3.1%) developed this complication (P <.0001). VOD was classified as mild in 7 (8%), moderate in 56 (64.4%), and severe in 24 (27.6%) cases. Sixteen patients died of VOD (corresponding to 1% of the whole series, 18.4% of VOD patients, and 66.7% of severe VOD). The use of unfractionated heparin did not significantly decrease the incidence of VOD. Independent variables associated with an increased risk of VOD were allogeneic BMT (relative risk [RR], 2.8; P <.001), pre-BMT elevation of serum aspartate aminotransferase (RR, 2.4; P =.001), high-dose cytoreductive therapy (RR, 2.3; P =.003), Karnofsky performance score less than 90% (RR, 2.7; P =.006), and prior abdominal radiation (RR, 2.9; P =.03). In conclusion, this prospective study shows that (1) the incidence of VOD is lower than that reported in smaller studies from single centers, (2) about one fourth of cases of VOD progress to severe disease, (3) main risk factors have a major impact on incidence of VOD, and (4) the use of prophylactic unfractionated heparin does not seem to reduce the incidence of VOD.     

A new chemical route to synthesize Cu–Ni alloy nanostructured particles

Cu–Ni alloys are extensively used in several metallurgic industries. The traditional methods for the synthesis of these alloys have some limitations, mainly related with manufacturing costs and product homogeneity, which makes evident the need to study and develop new methodologies to produce them. In this work, a new route for the synthesis of Cu–Ni alloys is presented. The process involves four steps, including the precursor preparation by the citrate-gel method and the subsequent decomposition, calcination and reduction. The products obtained in the different steps were characterized using thermal gravimetry (TG), X-ray diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), electron probe microanalysis (EPMA) and other techniques. The Cu–Ni alloy, of homogeneous composition, with a Cu/Ni atomic ratio of 0.92 and with a grain structure at nanometric scale was obtained using the proposed methodology. The studies carried out using SEM and XRD showed the alloy formation with a regular morphology and with an average grain size of about 15.5 nm. The thermal programmed reduction (TPR) profiles showed a unique reduction temperature for the synthesized solid, which is significantly lower than the pure oxides reduction temperature.     

BIONETS: Bio-Inspired Networking for Pervasive Communication Environments

This paper presents BIONETS, which is a novel bio-inspired approach to the design of localized services in pervasive communication/computing environments. Conventional networking approaches are not suitable for such scenarios, where they face three main issues, namely: 1) heterogeneity, 2) scalability, and 3) complexity. The proposed solution draws inspiration from the living world in terms of 1) evolutionary paradigms able to drive the adaptation process of autonomic services and 2) social paradigms for the provisioning of the necessary cooperation mechanisms. The net result is the introduction of autonomic self-evolving services that are able to adapt to localized needs and conditions while ensuring the maintenance of a purposeful system. Such a system requires scalable support from the communication standpoint. In networking terms, this results in the introduction of a two-tier architecture based on localized opportunistic exchanges of information. The presented approach is able to achieve better scalability properties when compared to more conventional communication approaches     

Optimal combined word-length allocation and architectural synthesis of digital signal processing circuits

In this brief, we address the combined application of word-length allocation and architectural synthesis of linear time-invariant digital signal processing systems. These two design tasks are traditionally performed sequentially, thus lessening the overall design complexity, but ignoring forward and backward dependencies that may lead to cost reductions. Mixed integer linear programming is used to formulate the combined problem and results are compared to the two-step traditional approach.