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Zhe Chang - One of the best experts on this subject based on the ideXlab platform.
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on the absence of a universal surface density and a maximum newtonian acceleration in dark matter haloes consequences for mond
arXiv: Astrophysics of Galaxies, 2020Co-Authors: Yong Zhou, A Del Popolo, Zhe ChangAbstract:We study the dark matter (DM) surface density using the SPARC sample and {compare} it to Donato et al. (2009) result. By means of MCMC method, we infer the best-fitting parameters for each galaxy. We reobtain the scaling relation between the surface density and luminosity, and several other scaling laws relating the dark matter halo properties to that of the galactic disc properties. We conclude, in contrast with Donato et al. \cite{Donato}, that the dark matter surface density is not a universal (Constant) Quantity but correlates with the luminosity as well as with other galactic disc properties. A derived posterior probability distribution of $\rho_0 r_0$ shows that the null hypothesis of constancy is rejected at a very high confidence level. These results leave little room for the claimed universality of dark matter surface density. Since MOND has strong prediction on the surface density \cite{Milgrom2009}, we compared our result with those predictions, finding that MOND predictions are violated by data. To strengthen the previous result, we compared our results to another prediction of MOND (Milgrom 2005), the existence of a maximum Newtonian dark matter acceleration in the halo. Also in this case, MOND predictions are in contradiction with data. The dark matter Newtonian acceleration correlates with all the previously presented galactic disc properties, and data are distributed outside the bound predicted by Milgrom $\&$ Sanders (Milgrom 2005). We also find that the null hypothesis (constancy of DM Newtonian acceleration) is rejected at a very high confidence level.
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on the absence of a universal surface density and a maximum newtonian acceleration in dark matter haloes consequences for mond
Physics of the Dark Universe, 2020Co-Authors: Yong Zhou, A Del Popolo, Zhe ChangAbstract:Abstract We study the dark matter (DM) surface density using the SPARC sample and compare it to Donato et al. (2009) result. By means of MCMC method, we infer the best-fitting parameters for each galaxy. We reobtain the scaling relation between the surface density and luminosity, and several other scaling laws relating the dark matter halo properties to that of the galactic disc properties. We conclude, in contrast with Donato et al. (2009), that the dark matter surface density is not a universal (Constant) Quantity but correlates with the luminosity as well as with other galactic disc properties. A derived posterior probability distribution of ρ 0 r 0 shows that the null hypothesis of constancy is rejected at a very high confidence level. These results leave little room for the claimed universality of dark matter surface density. Since MOND has strong prediction on the surface density (Milgrom, 2009), we compared our result with those predictions, finding that MOND predictions are violated by data. To strengthen the previous result, we compared our results to another prediction of MOND (Milgrom and Sanders, 2005), the existence of a maximum Newtonian dark matter acceleration in the halo. Also in this case, MOND predictions are in contradiction with data. The dark matter Newtonian acceleration correlates with all the previously presented galactic disc properties, and data are distributed outside the bound predicted by Milgrom and Sanders (2005). We also find that the null hypothesis (constancy of DM Newtonian acceleration) is rejected at a very high confidence level.
A Del Popolo - One of the best experts on this subject based on the ideXlab platform.
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on the absence of a universal surface density and a maximum newtonian acceleration in dark matter haloes consequences for mond
arXiv: Astrophysics of Galaxies, 2020Co-Authors: Yong Zhou, A Del Popolo, Zhe ChangAbstract:We study the dark matter (DM) surface density using the SPARC sample and {compare} it to Donato et al. (2009) result. By means of MCMC method, we infer the best-fitting parameters for each galaxy. We reobtain the scaling relation between the surface density and luminosity, and several other scaling laws relating the dark matter halo properties to that of the galactic disc properties. We conclude, in contrast with Donato et al. \cite{Donato}, that the dark matter surface density is not a universal (Constant) Quantity but correlates with the luminosity as well as with other galactic disc properties. A derived posterior probability distribution of $\rho_0 r_0$ shows that the null hypothesis of constancy is rejected at a very high confidence level. These results leave little room for the claimed universality of dark matter surface density. Since MOND has strong prediction on the surface density \cite{Milgrom2009}, we compared our result with those predictions, finding that MOND predictions are violated by data. To strengthen the previous result, we compared our results to another prediction of MOND (Milgrom 2005), the existence of a maximum Newtonian dark matter acceleration in the halo. Also in this case, MOND predictions are in contradiction with data. The dark matter Newtonian acceleration correlates with all the previously presented galactic disc properties, and data are distributed outside the bound predicted by Milgrom $\&$ Sanders (Milgrom 2005). We also find that the null hypothesis (constancy of DM Newtonian acceleration) is rejected at a very high confidence level.
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on the absence of a universal surface density and a maximum newtonian acceleration in dark matter haloes consequences for mond
Physics of the Dark Universe, 2020Co-Authors: Yong Zhou, A Del Popolo, Zhe ChangAbstract:Abstract We study the dark matter (DM) surface density using the SPARC sample and compare it to Donato et al. (2009) result. By means of MCMC method, we infer the best-fitting parameters for each galaxy. We reobtain the scaling relation between the surface density and luminosity, and several other scaling laws relating the dark matter halo properties to that of the galactic disc properties. We conclude, in contrast with Donato et al. (2009), that the dark matter surface density is not a universal (Constant) Quantity but correlates with the luminosity as well as with other galactic disc properties. A derived posterior probability distribution of ρ 0 r 0 shows that the null hypothesis of constancy is rejected at a very high confidence level. These results leave little room for the claimed universality of dark matter surface density. Since MOND has strong prediction on the surface density (Milgrom, 2009), we compared our result with those predictions, finding that MOND predictions are violated by data. To strengthen the previous result, we compared our results to another prediction of MOND (Milgrom and Sanders, 2005), the existence of a maximum Newtonian dark matter acceleration in the halo. Also in this case, MOND predictions are in contradiction with data. The dark matter Newtonian acceleration correlates with all the previously presented galactic disc properties, and data are distributed outside the bound predicted by Milgrom and Sanders (2005). We also find that the null hypothesis (constancy of DM Newtonian acceleration) is rejected at a very high confidence level.
Yong Zhou - One of the best experts on this subject based on the ideXlab platform.
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on the absence of a universal surface density and a maximum newtonian acceleration in dark matter haloes consequences for mond
arXiv: Astrophysics of Galaxies, 2020Co-Authors: Yong Zhou, A Del Popolo, Zhe ChangAbstract:We study the dark matter (DM) surface density using the SPARC sample and {compare} it to Donato et al. (2009) result. By means of MCMC method, we infer the best-fitting parameters for each galaxy. We reobtain the scaling relation between the surface density and luminosity, and several other scaling laws relating the dark matter halo properties to that of the galactic disc properties. We conclude, in contrast with Donato et al. \cite{Donato}, that the dark matter surface density is not a universal (Constant) Quantity but correlates with the luminosity as well as with other galactic disc properties. A derived posterior probability distribution of $\rho_0 r_0$ shows that the null hypothesis of constancy is rejected at a very high confidence level. These results leave little room for the claimed universality of dark matter surface density. Since MOND has strong prediction on the surface density \cite{Milgrom2009}, we compared our result with those predictions, finding that MOND predictions are violated by data. To strengthen the previous result, we compared our results to another prediction of MOND (Milgrom 2005), the existence of a maximum Newtonian dark matter acceleration in the halo. Also in this case, MOND predictions are in contradiction with data. The dark matter Newtonian acceleration correlates with all the previously presented galactic disc properties, and data are distributed outside the bound predicted by Milgrom $\&$ Sanders (Milgrom 2005). We also find that the null hypothesis (constancy of DM Newtonian acceleration) is rejected at a very high confidence level.
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on the absence of a universal surface density and a maximum newtonian acceleration in dark matter haloes consequences for mond
Physics of the Dark Universe, 2020Co-Authors: Yong Zhou, A Del Popolo, Zhe ChangAbstract:Abstract We study the dark matter (DM) surface density using the SPARC sample and compare it to Donato et al. (2009) result. By means of MCMC method, we infer the best-fitting parameters for each galaxy. We reobtain the scaling relation between the surface density and luminosity, and several other scaling laws relating the dark matter halo properties to that of the galactic disc properties. We conclude, in contrast with Donato et al. (2009), that the dark matter surface density is not a universal (Constant) Quantity but correlates with the luminosity as well as with other galactic disc properties. A derived posterior probability distribution of ρ 0 r 0 shows that the null hypothesis of constancy is rejected at a very high confidence level. These results leave little room for the claimed universality of dark matter surface density. Since MOND has strong prediction on the surface density (Milgrom, 2009), we compared our result with those predictions, finding that MOND predictions are violated by data. To strengthen the previous result, we compared our results to another prediction of MOND (Milgrom and Sanders, 2005), the existence of a maximum Newtonian dark matter acceleration in the halo. Also in this case, MOND predictions are in contradiction with data. The dark matter Newtonian acceleration correlates with all the previously presented galactic disc properties, and data are distributed outside the bound predicted by Milgrom and Sanders (2005). We also find that the null hypothesis (constancy of DM Newtonian acceleration) is rejected at a very high confidence level.
Nidhal Rezg - One of the best experts on this subject based on the ideXlab platform.
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impact of the corrective maintenance cost on manufacturing remanufacturing system performance
Modelling Computation and Optimization in Information Systems and Management Sciences, 2015Co-Authors: Sadok Turki, Zied Hajej, Nidhal RezgAbstract:This paper studies a manufacturing remanufacturing system composed by two parallel machines, a serviceable inventory, a remanufacturing inventory and a customer which demands a Constant Quantity of part. Taking into account the return of the used part and the maintenance action, discrete flow model is used to model and to simulate the system. The goal of this work is to evaluate the optimal serviceable inventory level which allows minimizing the sum of inventory, lost sales costs and the corrective maintenance cost. Numerical results are presented to show the impact of the corrective maintenance cost on the optimal serviceable inventory level.
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Infinitesimal perturbation analysis based optimization for a manufacturing-remanufacturing system
2013Co-Authors: Sadok Turki, Olivier Bistorin, Nidhal RezgAbstract:In this paper, a manufacturing/ remanufacturing system composed by two parallel machines, a manufacturing buffer, a recovery buffer and a customer who demands a Constant Quantity of product. To describe the system, a stochastic fluid model is adopted and which take into account returned products and remanufacturing products. The objective of this paper is to evaluate the optimal manufacturing buffer. This optimal level allows minimizing the total cost which is the sum of inventory and lost sales costs. Infinitesimal perturbation analysis is used for optimization of the manufacturing/ remanufacturing system. The trajectories of the buffer level are studied and the infinitesimal perturbation analysis estimates are evaluated. These estimates are shown to be unbiased and then they are implemented in an optimization algorithm which determines the optimal buffers levels in the presence of returned products and remanufacturing products.
Anshul Sheopuri - One of the best experts on this subject based on the ideXlab platform.
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analysis of tailored base surge policies in dual sourcing inventory systems
Management Science, 2015Co-Authors: Ganesh Janakiraman, Sridhar Seshadri, Anshul SheopuriAbstract:We study a model of a firm managing its inventory of a single product by sourcing supplies from two supply sources, a regular supplier who offers a lower unit cost and a longer lead time than a second, emergency, supplier. A practically implementable policy for such a firm is a tailored base-surge (TBS) policy [Allon G, Van Mieghem JA (2010) Global dual sourcing: Tailored base-surge allocation to near- and offshore production. Management Sci. 56(1):110–124] to manage its inventory. Under this policy, the firm procures a Constant Quantity from the regular supplier in every period and dynamically makes procurement decisions for the emergency supplier. Allon and Van Mieghem describe this practice as using the regular supplier to meet a base level of demand and the emergency supplier to manage demand surges, and they conjecture that this practice is most effective when the lead time difference between the two suppliers is large. We confirm these statements in two ways. First, we show the following analytical ...