242,475 research outputs found
Comparative analysis of VDMOS/LDMOS power transistors for RF amplifiers
A comparison between the RF performance of vertical and lateral power MOSFETs is presented. The role of each parasitic parameter in the assessment of the power gain, 1-dB compression point, efficiency, stability, and output matching is evaluated quantitatively using new analytical expressions derived from a ten-element model. This study reveals that the contribution of the parasitic parameter on degradation of performance depends upon the specific technology and generic perceptions of source inductance and feedback capacitance in VDMOS degradation may not always hold. This conclusion is supported by a detailed analysis of three devices of the same power rating from three different commercial vendors. A methodology for optimizing a device technology, specifically for RF performance and power amplifier performance is demonstrated
Cloud Control of Connected Vehicle under Bi-directional Time-varying delay: An Application of Predictor-observer Structured Controller
This article is devoted to addressing the cloud control of connected
vehicles, specifically focusing on analyzing the effect of bi-directional
communication-induced delays. To mitigate the adverse effects of such delays, a
novel predictor-observer structured controller is proposed which compensate for
both measurable output delays and unmeasurable, yet bounded, input delays
simultaneously. The study begins by novelly constructing an equivalent
delay-free inter-connected system model that incorporates the
Predictor-Observer controller, considering certain delay boundaries and model
uncertainties. Subsequently, a stability analysis is conducted to assess the
system's robustness under these conditions. Next, the connected vehicle lateral
control scenario is built which contain high-fidelity vehicle dynamic model.
The results demonstrate the controller's ability to accurately predict the
system states, even under time-varying bi-directional delays. Finally, the
proposed method is deployed in a real connected vehicle lateral control system.
Comparative tests with a conventional linear feedback controller showcase
significantly improved control performance under dominant bi-directional delay
conditions, affirming the superiority of the proposed method against the delay
Asterias: a parallelized web-based suite for the analysis of expression and aCGH data
Asterias (\url{http://www.asterias.info}) is an integrated collection of
freely-accessible web tools for the analysis of gene expression and aCGH data.
Most of the tools use parallel computing (via MPI). Most of our applications
allow the user to obtain additional information for user-selected genes by
using clickable links in tables and/or figures. Our tools include:
normalization of expression and aCGH data; converting between different types
of gene/clone and protein identifiers; filtering and imputation; finding
differentially expressed genes related to patient class and survival data;
searching for models of class prediction; using random forests to search for
minimal models for class prediction or for large subsets of genes with
predictive capacity; searching for molecular signatures and predictive genes
with survival data; detecting regions of genomic DNA gain or loss. The
capability to send results between different applications, access to additional
functional information, and parallelized computation make our suite unique and
exploit features only available to web-based applications.Comment: web based application; 3 figure
Detailed evaluation of data analysis tools for subtyping of bacterial isolates based on whole genome sequencing : Neisseria meningitidis as a proof of concept
Whole genome sequencing is increasingly recognized as the most informative approach for characterization of bacterial isolates. Success of the routine use of this technology in public health laboratories depends on the availability of well-characterized and verified data analysis methods. However, multiple subtyping workflows are now often being used for a single organism, and differences between them are not always well described. Moreover, methodologies for comparison of subtyping workflows, and assessment of their performance are only beginning to emerge. Current work focuses on the detailed comparison of WGS-based subtyping workflows and evaluation of their suitability for the organism and the research context in question. We evaluated the performance of pipelines used for subtyping of Neisseria meningitidis, including the currently widely applied cgMLST approach and different SNP-based methods. In addition, the impact of the use of different tools for detection and filtering of recombinant regions and of different reference genomes were tested. Our benchmarking analysis included both assessment of technical performance of the pipelines and functional comparison of the generated genetic distance matrices and phylogenetic trees. It was carried out using replicate sequencing datasets of high- and low-coverage, consisting mainly of isolates belonging to the clonal complex 269. We demonstrated that cgMLST and some of the SNP-based subtyping workflows showed very good performance characteristics and highly similar genetic distance matrices and phylogenetic trees with isolates belonging to the same clonal complex. However, only two of the tested workflows demonstrated reproducible results for a group of more closely related isolates. Additionally, results of the SNP-based subtyping workflows were to some level dependent on the reference genome used. Interestingly, the use of recombination-filtering software generally reduced the similarity between the gene-by-gene and SNP-based methodologies for subtyping of N. meningitidis. Our study, where N. meningitidis was taken as an example, clearly highlights the need for more benchmarking comparative studies to eventually contribute to a justified use of a specific WGS data analysis workflow within an international public health laboratory context
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