pc method
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Author(s):  
Mohammad Marufuzzaman ◽  
Muneed Anjum Timu ◽  
Jubayer Sarkar ◽  
Aminul Islam ◽  
Labonnah Farzana Rahman ◽  
...  

High-level architecture (HLA) and Distributed Interactive Simulation (DIS) are commonly used for the distributed system. However, HLA suffers from a resource allocation problem and to solve this issue, optimization of load balancing is required. Efficient load balancing can minimize the simulation time of HLA and this optimization can be done using the multi-objective evolutionary algorithms (MOEA). Multi-Objective Particle Swarm Optimization (MOPSO) based on crowding distance (CD) is a popular MOEA method used to balance HLA load. In this research, the efficiency of MOPSO-CD is further improved by introducing the passive congregation (PC) method. Several simulation tests are done on this improved MOPSO-CD-PC method and the results showed that in terms of Coverage, Spacing, Non-dominated solutions and Inverted generational distance metrics, the MOPSO-CD-PC performed better than the previous MOPSO-CD algorithm. Hence, it can be a useful tool to optimize the load balancing problem in HLA.


Author(s):  
Emmanuel Benichou ◽  
Nicolas Binder ◽  
Yannick Bousquet ◽  
Xavier Carbonneau

This paper introduces a semi-analytical approach which enables one to deal with distorted inflow in axial fans or compressors. It is inspired by the classical parallel compressor (PC) theory but relies on a local flow-loading coefficient formalism. It is applied to non-uniform flow conditions to study the aerodynamic behavior of a low-speed fan in response to upstream flow distortion. Experimental measurements and 3D RANS simulations are used to evaluate the prediction of fan performance obtained with the local PC method. The comparison proves that, despite its simplicity, the present approach enables to correctly capture first order phenomena, offering interesting perspectives for an early design phase if different fan geometries are to be tested and if the upstream distortion maps are available.


2021 ◽  
Author(s):  
praveen bm ◽  
Bharath K Devendra ◽  
Tripathi V S ◽  
Nagaraju DH ◽  
Nayana K O

Abstract Highly active Pt-Rh alloy catalyst coatings were developed by direct current (DC) and pulse current (PC) electrodeposition method for efficient hydrogen evolution reaction (HER) catalysts. The coatings were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM) linear sweep voltammetry (LSV) studies. Pt-Rh alloy catalyst coatings showed almost similar behavior as pure platinum metal.The Pt-Rh coating were obtained by PC method showed low over potentialfor HER. Very low slope of 41.2 mV/dec is obtained represents the Volmer-Tafel mechanistic path way for HER process. Chronopotentiometry was conducted and amount of hydrogen collected during these experiments was 24 ml for PC method 75% duty cycle sample.


2021 ◽  
Vol 15 ◽  
Author(s):  
Yixin Ji ◽  
Yutao Zhang ◽  
Haifeng Shi ◽  
Zhuqing Jiao ◽  
Shui-Hua Wang ◽  
...  

Brain functional networks (BFNs) constructed via manifold regularization (MR) have emerged as a powerful tool in finding new biomarkers for brain disease diagnosis. However, they only describe the pair-wise relationship between two brain regions, and cannot describe the functional interaction between multiple brain regions, or the high-order relationship, well. To solve this issue, we propose a method to construct dynamic BFNs (DBFNs) via hyper-graph MR (HMR) and employ it to classify mild cognitive impairment (MCI) subjects. First, we construct DBFNs via Pearson’s correlation (PC) method and remodel the PC method as an optimization model. Then, we use k-nearest neighbor (KNN) algorithm to construct the hyper-graph and obtain the hyper-graph manifold regularizer based on the hyper-graph. We introduce the hyper-graph manifold regularizer and the L1-norm regularizer into the PC-based optimization model to optimize DBFNs and obtain the final sparse DBFNs (SDBFNs). Finally, we conduct classification experiments to classify MCI subjects from normal subjects to verify the effectiveness of our method. Experimental results show that the proposed method achieves better classification performance compared with other state-of-the-art methods, and the classification accuracy (ACC), the sensitivity (SEN), the specificity (SPE), and the area under the curve (AUC) reach 82.4946 ± 0.2827%, 77.2473 ± 0.5747%, 87.7419 ± 0.2286%, and 0.9021 ± 0.0007, respectively. This method expands the MR method and DBFNs with more biological significance. It can effectively improve the classification performance of DBFNs for MCI, and has certain reference value for the research and auxiliary diagnosis of Alzheimer’s disease (AD).


Author(s):  
Daniel Tschopp ◽  
Pierre Delmas ◽  
Mathieu Rhedon ◽  
Sacha Sineux ◽  
Alexis Gonnelle ◽  
...  

The Performance Check (PC) method can be used for a simple check of the collector array performance of a solar thermal plant. It has been proposed recently as an input to a new ISO standard. This fact sheet provides an application of the PC method to large collector arrays. The goal of this fact sheet is to evaluate the methodology and provide practical insights for the application of the PC method.


2020 ◽  
Vol 20 (3) ◽  
pp. 147-158
Author(s):  
Mosleh M. Abualhaj ◽  
Sumaya N. Al-Khatib ◽  
Qusai Y. Shambour

AbstractVoice over IP (VoIP) wastes a valuable amount of bandwidth because of its large packet header size compared to its small packet payload. The main objective of this paper is to reduce the amount of this wasted bandwidth, by proposing a new packets coalescence method, called Payload Shrinking and Packets Coalesce (PS-PC). The proposed PS-PC method reduces the amount of the wasted bandwidth by i) coalesces a group of VoIP packets in one header instead of a separate header to each packet and ii) shrinks the VoIP packet payload to a smaller one based on a certain algorithm. The proposed PS-PC method is deployed at the sender side VoIP gateway that represents an exit point to a myriad number of simultaneous VoIP calls. The performance evaluation showed better bandwidth usage when deploying the proposed PS-PC method with ITTP protocol in comparison to the traditional ITTP protocol without the PS-PC method.


2019 ◽  
Vol 109 (5) ◽  
pp. 2063-2072 ◽  
Author(s):  
Maxime Lacour ◽  
Norman A. Abrahamson

Abstract A computationally efficient methodology for propagating the epistemic uncertainty in the median ground motion in probabilistic seismic hazard analysis is developed using the polynomial chaos (PC) approach. For this application, the epistemic uncertainty in the median ground motion for a specific scenario is assumed to be lognormally distributed and fully correlated across earthquake scenarios. In the hazard calculation, a single central ground‐motion model (GMM) is used for the median along with the epistemic standard error of the median for each scenario. A set of PC coefficients is computed for each scenario and each test ground‐motion level. The additional computation burden in computing these PC coefficients depends on the order of the approximation but is less than computing the median ground motion from one additional GMM. With the PC method, the mean and fractiles of the hazard due to the epistemic uncertainty distribution of the median ground motion are computed as a postprocess that is very fast computationally. For typical values of the standard deviation of epistemic uncertainty in the median ground motion (<0.2 natural log units), the methodology accurately estimates the epistemic uncertainty distribution of the hazard over the 1%–99% range. This full epistemic range is not well modeled with just a small number of GMM branches uses in the traditional logic‐tree approach. The PC method provides more accuracy, faster computation, and reduced memory requirements than the traditional approach. For large values of the epistemic uncertainty in the median ground motion, a higher order of the PC expansion may be needed to be included to capture the full range of the epistemic uncertainty.


Author(s):  
Fatma Abid ◽  
Abdelkhalak Elhami ◽  
Tarek Merzouki ◽  
Hassen Trabelsi ◽  
Lassaad Walha ◽  
...  

This paper proposes a methodology for taking into consideration uncertainties based on polynomial chaos (PC). The proposed approach is used in order to determine the response of Cu-Al-Zn-Mn shape memory alloy specimen with uncertainties associated to material parameters. The simulation results are obtained by PC method. The proposed method seems to be an efficient probabilistic tool. It is worth mentioning that PC approach is an interesting alternative for the parametric studies. This technique is more efficient compared to MC approach.


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