ABSTRACT
Wireless Sensor Networks are subjected to some design constraints (e.g., processing capability, storage memory, energy consumption, fixed deployment, etc.) and to outdoor harsh conditions that deeply affect the network reliability. The aim of this work is to provide a deeper understanding about the way redundancy and node deployment affect the network reliability. In more detail, the paper analyzes the design and implementation of a wireless sensor network for low-power and low-cost applications and calculates its reliability considering the real environmental conditions and the real arrangement of the nodes deployed in the field. The reliability of the system has been evaluated by looking for both hardware failures and communication errors. A reliability prediction based on different handbooks has been carried out to estimate the failure rate of the nodes self-designed and self-developed to be used under harsh environments. Then, using the Fault Tree Analysis the real deployment of the nodes is taken into account considering the Wi-Fi coverage area and the possible communication link between nearby nodes. The findings show how different node arrangements provide significantly different reliability. The positioning is therefore essential in order to obtain maximum performance from a Wireless sensor network.
Subject(s)
Computer Communication Networks , Wireless Technology , Agriculture , Farms , Reproducibility of ResultsABSTRACT
In archaeological applications the accurate reconstruction of buried structures is mandatory. Electrical resistivity tomography is widely used for this purpose. Nevertheless, resistivity errors could be generated by wrong placement of electrodes. Papers in the literature do not discuss the influence of errors connected with the electrode position location (GPS-error). In this paper the first results of a Monte Carlo simulation analysis of data acquired on a tumulus are presented. The main research questions were: (i) if it is correct to ignore the GPS-error collect, and (ii) if a minimum threshold, that significantly affect the inversion, exists. Results, obtained considering planimetric GPS-errors of about one third of the fixed electrode distances, show that the GPS-errors affect resistivity, but the generated errors/anomalies: (a) are lower than that obtained without considering the topography, and (b) are significant from a numerical point of view, but do not affect the interpretation, being compatible with the soil resistivity ranges.
ABSTRACT
Genomic datasets are growing dramatically as the cost of sequencing continues to decline and small sequencing devices become available. Enormous community databases store and share these data with the research community, but some of these genomic data analysis problems require large-scale computational platforms to meet both the memory and computational requirements. These applications differ from scientific simulations that dominate the workload on high-end parallel systems today and place different requirements on programming support, software libraries and parallel architectural design. For example, they involve irregular communication patterns such as asynchronous updates to shared data structures. We consider several problems in high-performance genomics analysis, including alignment, profiling, clustering and assembly for both single genomes and metagenomes. We identify some of the common computational patterns or 'motifs' that help inform parallelization strategies and compare our motifs to some of the established lists, arguing that at least two key patterns, sorting and hashing, are missing. This article is part of a discussion meeting issue 'Numerical algorithms for high-performance computational science'.
ABSTRACT
Purpose The aim of this study was to evaluate the mid- to long-term outcomes and complications in patients affected by rheumatic diseases treated with the Universal 2 (U2) total wrist arthroplasty (TWA). Methods We reviewed, in a retrospective, noncontrolled cohort study, 22 patients affected by rheumatoid arthritis (RA), who underwent U2 total wrist replacement between March 2003 and January 2014 for the treatment of 23 rheumatoid wrists with the aim of obtaining the remission of pain and a range of motion (ROM) useful for daily activities, according to the patients' demands, as an alternative to total wrist arthrodesis. The cohort of patients included 20 females and 2 males, with a mean age of 54.9 years. Residual pain, preoperative ROM, postoperative ROM increases, grip strength, radiographic changes, long-term complications, and reasons for revision or failures were evaluated. Results In this study, 22 patients were evaluated at a mean follow-up of 82.3 months (range: 2-12 years). All patients had good or complete pain relief, the mean visual analogue scale pain score was 0.82. The mean grip strength improved and postoperatively was 11 kg (Jamar). The mean total ROM of flexion-extension was 72.3 degrees; radial-ulnar deviation 24.9 degrees. The mean QuickDASH score of 49 and patient rate wrist/hand evaluation of 41.7 a revision surgical procedure in six cases (26%): in two cases, a carpal component revision procedure and in four cases, total implant failures requiring either conversion to a Swanson spacer or wrist joint fusion. Conclusion TWA provides pain relief, preserves motion, and improves function in severe degenerative RA. Our results at a mid- to long-term follow-up with the U2 prosthesis were encouraging and represent, when indicated, a valid alternative to fusion which is less appealing for RA patients. Level of Evidence Level of evidence is therapeutic IV.
