132,551 research outputs found
Comparison of Direct Multiobjective Optimization Methods for the Design of Electric Vehicles
No full text"System design oriented methodologies" are discussed in this paper through the comparison of multiobjective optimization methods applied to heterogeneous devices in electrical engineering. Avoiding criteria function derivatives, direct optimization algorithms are used. In particular, deterministic geometric methods such as the Hooke & Jeeves heuristic approach are compared with stochastic evolutionary algorithms (Pareto genetic algorithms). Different issues relative to convergence rapidity and robustness on mixed (continuous/discrete), constrained and multiobjective problems are discussed. A typical electrical engineering heterogeneous and multidisciplinary system is considered as a case study: the motor drive of an electric vehicle. Some results emphasize the capacity of each approach to facilitate system analysis and particularly to display couplings between optimization parameters, constraints, objectives and the driving mission
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Loss comparison of 2 and 3-level inverter topologies
No full textThis paper investigates semiconductor and DC-link capacitor losses in two two-level and two three-level voltage source inverters. The components of the four inverters are selected to have appropriate voltage and current ratings. Analytical expressions for semiconductor losses are reviewed and expressions for DC link capacitor losses are derived for all topologies. Three-level inverters are found to have lower semiconductor losses, but higher DC-link capacitor losses. Overall, the three-level Neutral-Point-Clamped inverter proved to be the most efficient topology
Multi-phase System Supplied by SVM VSI: A New Fast Algorithm to Compute Duty Cycles
No full textLa version éditeur de cette article est disponible à l'adresse suivante : http://www.epe-association.org/epe/index.phpMany authors proposed SVM VSI applied to multi-phase drives
IHC of metastin expression in the placentas of control A (A), ePE (B), control B (C), lPE (D), isotype control (E), positive control (F), and negative control (G).
No full text<p>Panel H shows metastin immunity intensity score semiquantitation. Metastin staining is present in both syncytiotrophoblasts and cytotrophoblasts from Control A, ePE, Control B and lPE (A–D). Trophoblasts from ePE had higher expression of metastin as compared to control A (A, B). lPE had the same intensity expression of metastin as compared with control B (C,D). ePE had significantly higher expression of metastin as compared with control A and lPE (H). Red arrows indicate the syncytiotrophoblast; Black arrows indicate the cytotrophoblast.</p
Bond Graph Based Stability Analysis of a Railway Traction System
No full textThis paper emphasises the interest of the Bond Graph approach for analysis and system design of heterogeneous and multi-field devices. In particular, the local stability analysis of non linear systems can be directly derived from the linearised Causal Bond Graph. This method is applied to a typical electrical engineering system: a railway traction device involving electromechanical couplings. Validity, usefulness and originality of this approach are displaye
Systemic design of multidisciplinary electrical energy devices: a pedagogical approach
No full textIn this paper, we present a complete educative project for illustrating the design and the analysis of hybrid electrical systems. It is based on the study of an ElectroHydrostatic Actuator for flight control application, fed by a power supply associating a PEM fuel cell with a ultracapacitor storage. This system is controlled to achieve a typical energy management strategy of this multi source structure.
Step by step, student can faces typical issues relative to the design of heterogenous and multidisciplinary devices by achieving eight pedagogical objectives. These eight targets are focused on methodological approach for multi domain modelling (Bond Graphs), causal analysis, but also on simulation of complex heterogeneous systems. A typical hybrid system feeding an ElectroHydrostatic Actuator (EHA) for flight control application has to be designed which drives students towards other pedagogical objectives: system based device sizing (fuel cell and ultracapacitor), energy management, system analysis
IHC of GPR54 expression in the placentas of Control A (A), ePE (B), Control B (C), lPE (D), isotype control (E), positive control (F), negative control (G).
No full text<p>Panel H shows GPR54 immunity intensity score semiquantitation. GPR54 was detected in syncytiotrophoblast from ePE and Control A, and hardly detected from lPE and Control B. Trophoblast from the ePE demonstrated no differences in GPR54 expression with Control A (H). Red arrows indicate the syncytiotrophoblast; black arrows indicate the cytotrophoblast.</p
Effect of motif insertion position on EPE.
No full text(A) EPE of Hoxc9 motif on EPE from DeepAccess model trained to predict motor neuron chromatin accessibility shows EPE of Hoxc9 motifs are low for positions in the beginning of the DNA sequence and high for positions at the middle and end of the DNA sequence. (B) Scatter plot of EPEs for 356 HOCOMOCOv11 mouse transcription factor motifs when insertion is at position 0 compared to position 50 indicate early insertion site in DNA sequence results in different EPE values for transcription factors, with some having lower EPEs and others having higher EPEs. (C) Scatter plot of EPEs for 356 HOCOMOCOv11 mouse transcription factor motifs when insertion is at position 70 compared to position 50 indicate early insertion site in DNA sequence results in similar EPE values for all transcription factors. (D) Heatmap of Pearson’s r of EPEs for DeepAccess motor neuron accessibility for insertions at all starting positions within the DNA sequence shows most insertion positions result in highly similar EPEs except for early insertion positions. (E) Heatmap of Pearson’s r of DEPEs for DeepAccess motor neuron vs fibroblast differential accessibility for insertions at all starting positions within the DNA sequence shows most insertion positions result in highly similar EPEs except for early insertion positions. (F) Row z-score normalized EPEs for DeepAccess motor neuron accessibility at each position show most motifs have higher EPEs when inserted at a position in the center of the DNA sequence. Some motifs (like Sp motifs) have higher EPEs at the beginning of the DNA sequence. (TIF)</p
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