Intelligent adaptive underwater sensor networks

Autonomous Underwater Vehicle (AUV) technology has reached a sufficient maturity level to be considered a suitable alternative to conventional Mine Countermeasures (MCM). Advantages of using a network of AUVs include time and cost efficiency, no personnel in the minefield, and better data collection. A major limitation for underwater robotic networks is the poor communication channel. Currently, acoustics provides the only means to send messages beyond a few metres in shallow water, however the bandwidth and data rate are low, and there are disturbances, such as multipath and variable channel delays, making the communication non-reliable. The solution this thesis proposes using a network of AUVs for MCM is the Synchronous Rendezvous (SR) method --- dynamically scheduling meeting points during the mission so the vehicles can share data and adapt their future actions according to the newly acquired information. Bringing the vehicles together provides a robust way of exchanging messages, as well as means for regular system monitoring by an operator. The gains and losses of the SR approach are evaluated against a benchmark scenario of vehicles having their tasks fixed. The numerical simulation results show the advantage of the SR method in handling emerging workload by adaptively retasking vehicles. The SR method is then further extended into a non-myopic setting, where the vehicles can make a decision taking into account how the future goals will change, given the available resource and estimation of expected workload. Simulation results show that the SR setting provides a way to tackle the high computational complexity load, common for non-myopic solutions. Validation of the SR method is based on trial data and experiments performed using a robotics framework, MOOS-IvP. This thesis develops and evaluates the SR method, a mission planning approach for underwater robotic cooperation in communication and resource constraint environment

Environmental impact assessment of discharge of treated wastewater effluent in Upper Iskar sub-catchment

The upper Iskar sub-catchment is one of Bulgaria’s most important economic and socially significant water sources because of its role in supplying Sofia with drinking water. Among the critical factors that carry potential high-risk levels for water quality in this hydrosystem are the discharge from the Samokov Wastewater Treatment Plant (WWTP), diffuse pollution from agriculture, and the percolation of untreated sewage from the small villages. In this study, we assessed the effect of treated wastewater effluent on water quality, and on the ecological state and microbial communities in the river sector of Samokov’s WWTP discharge area. The assessment was based on the complex use of chemical and microbiological indicators and biological quality elements. The concentrations of organics, nutrients and microcomponents were determined with results confirming the expected increase for parameters associated with the discharge of urban wastewater. The ecological state, according to macrozoobenthos indicators, was “good” throughout the river sector but local deterioration was registered in a proximal location downstream of the WWTP outfall. The analysis of stream water and bed sediment microbial communities by a fluorescent technique showed the high metabolic activity and intensive transformation processes in addition to high abundance registered with standard cultivation methods. The importance of the studied sub-catchment for the functioning of the urban water cycle, and for the quality of Sofia’s drinking water, underlines the need to extend an existing monitoring program with a more detailed assessment of the environmental impact of wastewater discharge

Founder p.Arg 446* mutation in the PDHX gene explains over half of cases with congenital lactic acidosis in Roma children

Investigation of 31 of Roma patients with congenital lactic acidosis (CLA) from Bulgaria identified homozygosity for the R446* mutation in the PDHX gene as the most common cause of the disorder in this ethnic group. It accounted for around 60% of patients in the study and over 25% of all CLA cases referred to the National Genetic Laboratory in Bulgaria. The detection of a homozygous patient from Hungary and carriers among population controls from Romania and Slovakia suggests a wide spread of the mutation in the European Roma population.The clinical phenotype of the twenty R446* homozygotes was relatively homogeneous, with lactic acidosis crisis in the first days or months of life as the most common initial presentation (15/20 patients) and delayed psychomotor development and/or seizures in infancy as the leading manifestations in a smaller group (5/20 patients). The subsequent clinical picture was dominated by impaired physical growth and a very consistent pattern of static cerebral palsy-like encephalopathy with spasticity and severe to profound mental retardation seen in over 80% of cases. Most patients had a positive family history.We propose testing for the R446* mutation in PDHX as a rapid first screening in Roma infants with metabolic acidosis. It will facilitate and accelerate diagnosis in a large proportion of cases, allow early rehabilitation to alleviate the chronic clinical course, and prevent further affected births in high-risk families