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1.
Khoder Makkawi Nourdine Ait-Tmazirte Maan El Badaoui El Najjar Nazih Moubayed 《Entropy (Basel, Switzerland)》2021,23(4)
When applying a diagnostic technique to complex systems, whose dynamics, constraints, and environment evolve over time, being able to re-evaluate the residuals that are capable of detecting defaults and proposing the most appropriate ones can quickly prove to make sense. For this purpose, the concept of adaptive diagnosis is introduced. In this work, the contributions of information theory are investigated in order to propose a Fault-Tolerant multi-sensor data fusion framework. This work is part of studies proposing an architecture combining a stochastic filter for state estimation with a diagnostic layer with the aim of proposing a safe and accurate state estimation from potentially inconsistent or erroneous sensors measurements. From the design of the residuals, using α-Rényi Divergence (α-RD), to the optimization of the decision threshold, through the establishment of a function that is dedicated to the choice of α at each moment, we detail each step of the proposed automated decision-support framework. We also dwell on: (1) the consequences of the degree of freedom provided by this α parameter and on (2) the application-dictated policy to design the α tuning function playing on the overall performance of the system (detection rate, false alarms, and missed detection rates). Finally, we present a real application case on which this framework has been tested. The problem of multi-sensor localization, integrating sensors whose operating range is variable according to the environment crossed, is a case study to illustrate the contributions of such an approach and show the performance. 相似文献
2.
Frank Nielsen 《Entropy (Basel, Switzerland)》2021,23(4)
We generalize the Jensen-Shannon divergence and the Jensen-Shannon diversity index by considering a variational definition with respect to a generic mean, thereby extending the notion of Sibson’s information radius. The variational definition applies to any arbitrary distance and yields a new way to define a Jensen-Shannon symmetrization of distances. When the variational optimization is further constrained to belong to prescribed families of probability measures, we get relative Jensen-Shannon divergences and their equivalent Jensen-Shannon symmetrizations of distances that generalize the concept of information projections. Finally, we touch upon applications of these variational Jensen-Shannon divergences and diversity indices to clustering and quantization tasks of probability measures, including statistical mixtures. 相似文献
3.
Dariusz Marek Adam Domaski Joanna Domaska Jakub Szygua Tadeusz Czachrski Jerzy Klamka 《Entropy (Basel, Switzerland)》2021,23(5)
In this article, a way to employ the diffusion approximation to model interplay between TCP and UDP flows is presented. In order to control traffic congestion, an environment of IP routers applying AQM (Active Queue Management) algorithms has been introduced. Furthermore, the impact of the fractional controller and its parameters on the transport protocols is investigated. The controller has been elaborated in accordance with the control theory. The TCP and UDP flows are transmitted simultaneously and are mutually independent. Only the TCP is controlled by the AQM algorithm. Our diffusion model allows a single TCP or UDP flow to start or end at any time, which distinguishes it from those previously described in the literature. 相似文献
4.
We address the problem of telegraphic transport in several dimensions. We review the derivation of two and three dimensional telegrapher’s equations—as well as their fractional generalizations—from microscopic random walk models for transport (normal and anomalous). We also present new results on solutions of the higher dimensional fractional equations. 相似文献
5.
Traditional cell/particle isolation methods are time-consuming and expensive and can lead to morphology disruptions due to high induced shear stress. To address these problems, novel lab-on-a-chip-based purification methods have been employed. Among various methods introduced for the separation and purification of cells and synthetics particles, acoustofluidics has been one of the most effective methods. Unlike traditional separation techniques carried out in clinical laboratories based on chemical properties, the acoustofluidic process relies on the physical properties of the sample. Using acoustofluidics, manipulating cells and particles can be achieved in a label-free, contact-free, and highly biocompatible manner. To optimize the functionality of the platform, the numerical study should be taken into account before conducting experimental tests to save time and reduce fabrication expenses. Most current numerical studies have only considered one-dimensional harmonic standing waves to simulate the acoustic pressure distribution. However, one-dimensional simulations cannot calculate the actual acoustic pressure distribution inside the microchannel due to its limitation in considering longitudinal waves. To address this limitation, a two-dimensional numerical simulation was conducted in this study. Our numerical simulation investigates the effects of the platform geometrical and operational conditions on the separation efficiency. Next, the optimal values are tested in an experimental setting to validate these optimal parameters and conditions. This work provides a guideline for future acoustofluidic chip designs with a high degree of reproducibility and efficiency. 相似文献
6.
We investigate the possibility of phantom crossing in the dark energy sector and the solution for the Hubble tension between early and late universe observations. We use robust combinations of different cosmological observations, namely the Cosmic Microwave Background (CMB), local measurement of Hubble constant (), Baryon Acoustic Oscillation (BAO) and SnIa for this purpose. For a combination of CMB+BAO data that is related to early universe physics, phantom crossing in the dark energy sector was confirmed at a 95% confidence level and we obtained the constraint km/s/Mpc at a 68% confidence level, which is in perfect agreement with the local measurement by Riess et al. We show that constraints from different combinations of data are consistent with each other and all of them are consistent with phantom crossing in the dark energy sector. For the combination of all data considered, we obtained the constraint km/s/Mpc at a 68% confidence level and the phantom crossing happening at the scale factor at a 68% confidence level. 相似文献
7.
近年来以低温室效应(GWP)的制冷剂的蒸汽压缩式高温热泵一直是余热回收领域的研究热点。为获得更高的输出温度,本课题组搭建了一台采用自然工质水作为循环冷媒的超高温热泵样机并进行了实验测试。实验结果表明蒸发温度为80℃,冷凝温度从115℃升至145℃时,热泵的COP从4.88降至1.89。在85℃蒸发,117℃冷凝时,最高COP为6.1,制热量为285 kW,同时在85℃蒸发时,该热泵的最高冷凝温度可达到150℃,此时COP为1.96。在相同的温升下,热泵的COP和卡诺效率都随着输出温度的升高而增加,因此我们认为该热泵更适合高温输出的应用场合。 相似文献
8.
In this paper, we deal with an SIRS reaction–diffusion epidemic model with saturation infection mechanism. Based on the uniform boundedness of the parabolic system, we investigate the extinction and persistence of the infectious disease in terms of the basic reproduction number. To better investigate the effects of infection mechanism and individual diffusion, we further analyze the asymptotic profiles of the endemic equilibrium for small or large motility rate and large saturation rate. In particular it is shown that large saturation may cause the elimination of disease. Our study may provide some significant useful insight on disease control and prevention. 相似文献
9.
ZHANG Xu BAI Xue-bing WANG Xue-pei LI Xin-wu LI Zhi-gang ZHANG Xiao-shuan 《光谱学与光谱分析》2021,41(11):3377-3384
为提高生鲜羊肉储存期内(4,8和20 ℃环境)挥发性盐基氮(TVB-N)的近红外光谱(NIR)检测的稳定性和准确性,选取特征光谱和预测模型是关键步骤。以121个羊肉样品为实验对象,采集生鲜羊肉680~2 600 nm波段的近红外光谱。以多元散射校正(MSC)、标准正态变换(SNV)等散射校正方法,Savitzky-Golay卷积平滑(SGS)、移动平均平滑(MAS)等平滑处理方法,以及归一化(Normalization)、中心化(Centering)、标准化(Autoscaling)等尺度缩放方法分别预处理光谱数据后建立偏最小二乘法(PLS)预测模型。比较发现SGS处理的光谱建模效果最好。利用蒙特卡洛采样(MCS)法及马氏距离法(MD)消除了羊肉光谱的5个异常数据。运用光谱-理化值共生距离(SPXY)算法划分总样本的75%(87个)为校正集样本,剩余29个为验证集样本,利用竞争性自适应重加权法(CARS)、无信息变量消除法(UVE)、改进的无信息变量消除法(IUVE)和连续投影算法(SPA)提取特征光谱得到的波长个数分别为14,713,144和15。将全光谱和4种方法提取的特征波长作为输入变量建立预测模型,CARS提取的波长所建立模型的性能优于UVE、IUVE和SPA提取的波长所建立模型的性能,表明CARS方法可以有效简化输入变量并提高预测模型的性能。改进后得到的IUVE法相比于UVE法,筛选出的波长数更少且模型性能有所提升。以提取的特征波长建立PLS,支持向量机(SVM)和最小二乘支持向量机(LS-SVM)预测模型,SVM模型得到最优的校正集预测结果,其中CARS-SVM预测模型的校正决定系数(R2C)和校正均方根误差(RMSEC)分别为0.939 1和1.426 7,最优的验证集预测效果为LS-SVM预测模型得到,其中IUVE-LS-SVM预测模型的验证决定系数(R2V)和验证均方根误差(RMSEV)分别为0.856 8和1.886 2。基于近红外特征光谱建立简化、优化的生鲜羊肉储存期TVB-N预测模型,为实现快速无损检测生鲜羊肉中的TVB-N浓度提供技术支持。 相似文献
10.
利用传统支持向量机(SVM)对不平衡数据进行分类时,由于真实的少数类支持向量样本过少且难以被识别,造成了分类时效果不是很理想.针对这一问题,提出了一种基于支持向量机混合采样的不平衡数据分类方法(BSMS).该方法首先对经过支持向量机分类的原始不平衡数据按照所处位置的不同划分为支持向量区(SV),多数类非支持向量区(MNSV)以及少数类非支持向量区(FNSV)三个区域,并对MNSV区和FNSV区的样本做去噪处理;然后对SV区分类错误和部分分类正确且靠近决策边界的少数类样本重复进行过采样处理,直到找到测试结果最优的训练数据集;最后有选择的随机删除MNSV区的部分样本.实验结果表明:方法优于其他采样方法. 相似文献